The Impact of Firefighters’ Emotional Labor on Job Performance: The Moderating Effects of Transactional and Transformational Leadership

Abstract

Our study leverages insights from the conservation of resources theory and job demands–resources theory to explore the relationship between two types of emotional labor—surface acting and deep acting—and job performance among firefighters. Furthermore, we assess the moderating roles of transactional and transformational leadership within this framework. Using hierarchical multiple regression models, we analyzed data from 1453 firefighters in Gyeonggi-do, South Korea’s most populous province. The findings reveal that surface acting adversely affects job performance, whereas deep acting exerts no significant impact. The relationships between these two types of emotional labor are contingent on transactional and transformational leadership. The policy implications of this study include the need to manage employees’ emotional labor by distinguishing between surface and deep acting as well as the need for efforts and alternatives to facilitate transactional and transformational leadership.

1. Introduction

According to extensive research on the mental health of firefighters, firefighters frequently encounter high levels of stress and dangerous situations [1,2,3]. As public employees, they perform various duties in South Korea, such as disaster management, emergency rescue, and fire suppression [4]. They are exposed to numerous hazards, including physical threats such as smoke, fire, and noise, as well as mental stress and trauma. Firefighting, in particular, involves extremely hazardous elements such as smoke and toxic gases, limited flame visibility, and physical dangers related to collapsing structures [5]. Emergency rescue tasks demand swift and precise responses to life-threatening situations, including traffic accidents, mountain rescues, and other emergencies [6]. These scenarios place immense physical and mental pressure on firefighters [7]. To learn to cope with these challenging situations, firefighters undergo thorough education and training [8]. However, this training cannot singlehandedly preclude all sources of stress. Firefighters remain at risk of mental health issues, a vulnerability that becomes more pronounced during periods of increased stress, such as the COVID-19 pandemic [9]. The pandemic has compounded firefighters’ stress by imposing additional responsibilities (e.g., disinfection duties), the risk of infection, and limitations on face-to-face interactions [10]. The severe psychological stress and fatigue faced by firefighters have particularly detrimental effects on their work motivation and capabilities [1]. The continuous high-intensity work and sustained tension significantly strain their physical and mental health [11]. As a result, firefighters may experience reduced concentration, impaired decision-making abilities, and a general decline in job performance.

This study analyzes the impact of emotional labor on job performance, particularly in relation to firefighters who are on the front lines of public service, providing fire prevention, emergency response, and rescue services. We anticipate a decline in firefighters’ performance as their emotional labor increases. Emotional labor encompasses two main types of behavior: surface acting, wherein individuals conceal their true emotions, and deep acting, wherein they genuinely experience and express emotions that align with organizational expectations [12,13]. According to the conservation of resources (CoR) theory, surface acting depletes personal resources and induces stress due to the continuous mental effort it requires, whereas deep acting can lead to positive stress and revitalization by precipitating rewarding interactions with the public [14,15]. For instance, a firefighter engaging in surface acting may feel fear or anxiety but strive to maintain a calm exterior, thus resulting in ongoing mental strain, increased energy consumption, and elevated stress levels [16,17]. Conversely, a firefighter practicing deep acting adjusts their emotions to genuinely feel calm and confident, gaining positive energy and rejuvenation from their interactions with the public [17,18]. As a result, this study predicts that surface acting exerts a negative impact on job performance, whereas deep acting has a positive association with job performance. From this perspective, we highlight the importance of emotional labor strategies and emotional intelligence for firefighters and seek to identify methods to enhance job performance by harnessing these factors.

This study investigates the influence of human resource management strategies based on the job demands–resources (JD-R) theory, which focuses on the relationship between emotional labor and job performance [14,19]. It highlights the significance of contextual factors that extend beyond the direct effects of emotional labor, proposing that job resources can mitigate the negative impacts of emotional demands [20]. The study specifically identifies transactional and transformational leadership as key moderating factors. We suggest that effective leadership can improve firefighters’ mental and emotional well-being, thereby restoring their emotional resources [17]. Transactional leadership focuses on the clear definition of roles and task requirements, coupled with extrinsic rewards and punishments contingent on the fulfillment of these obligations. This leadership style emphasizes structured exchanges between leaders and followers, where compliance and performance are incentivized through rewards and penalties [21,22]. Conversely, transformational leadership involves inspiring and motivating followers to exceed their typical performance levels by aligning their personal values and goals with those of the organization. Transformational leaders foster innovation, intellectual growth, and a deep emotional commitment to the organization’s vision, which enhances employees’ job satisfaction and performance [23,24].

For example, transactional leadership, as outlined by the JD-R theory, helps manage the balance between job demands and resources, which is essential for firefighters’ performance. By establishing clear expectations and a system of rewards and penalties, transactional leaders prevent resource depletion by maintaining a stable work environment and minimizing oversight, thereby supporting efficient resource utilization. Meanwhile, transformational leadership boosts morale and performance by presenting achievable visions and personalized support that enhance employees’ emotional energy and intellectual growth. This style of leadership empowers firefighters, promoting innovative problem solving and resilience, especially in managing the emotional demands of their roles. Both leadership styles play complementary roles in optimizing firefighters’ job performance by effectively managing their resources and demands, aligning with the JD-R model’s focus on maintaining a balance that supports employee well-being and efficacy in high-pressure environments.

Our research makes two key contributions to the public mental health literature. First, it enhances our understanding of emotional labor strategies by examining the effects of surface and deep acting on firefighters’ job performance. Although firefighters frequently encounter situations that necessitate emotional regulation, the impact of emotional labor on job performance has received scant attention. Our findings suggest that as firefighters are confronted with higher emotional demands during public interactions, their efforts were correlated with a decrease in performance. This has clear implications for both firefighters and fire organizations. Second, the study expands on the existing collective knowledge regarding emotional labor by investigating how transactional and transformational leadership moderate the relationship between emotional labor and job performance. We propose that supportive leadership acts as a valuable job resource that can mitigate the negative effects of emotional labor. Moreover, our research provides an important practical insight: If firefighters receive adequate organizational support, they can effectively deliver services and fulfill public needs even under high job demands.

This study was conducted as follows: First, we reviewed the previous research on emotional labor and job performance. Then, we proposed research hypotheses based on the theoretical foundations regarding the characteristics of transactional and transformational leadership as moderating factors in the relationship between emotional labor and job performance. To test these hypotheses, we utilized the survey data collected by the Gyeonggi Provincial Council in 2020. Based on the analysis results, we developed theoretical and policy implications.

2. Theoretical Background and Hypotheses

2.1. The Impact of Emotional Labor on Job Performance

In “The Managed Heart,” Hochschild [25], an American sociologist, defined emotional labor as “the management of emotions in order to produce outward facial expressions or gestures.” Similarly, Ashforth and Humphrey [26] defined emotional labor as the required expression of emotions, emphasizing adherence to outward display rules rather than focusing on internal feelings. According to Morris and Feldman [27], emotional labor encompasses the planning, control, and effort needed to appropriately express the emotions desired by the employer during interactions with others. Unlike machines, human employees can feel, express, and regulate their emotions, making emotional labor management vital for both individual and organizational outcomes [28,29]. In fire organizations, in which emotionally charged events are common, firefighters must manage their emotions effectively, even when these emotions do not align with the agency’s display requirements.

Hochschild [25] identified two types of emotional labor: surface acting, in which workers conform to organizational norms of expression by making external expressions without exhibiting displeasure, and deep acting, in which workers attune their actual emotions to the emotional state of the other person. Surface acting involves simulating emotions one does not genuinely feel and suppressing one’s true feelings, typically for the benefit of an audience such as customers or the public [16,17]. This approach is commonly employed by employees to conceal their real emotions or display emotions they are not actually experiencing, referred to as the “malicious faking” strategy [30]. This strategy includes disguising or modifying internal negative emotions to appear superficially acceptable [31]. Conversely, deep acting represents a form of emotional labor wherein employees strive to genuinely feel the emotions required by their roles, thereby aligning their true feelings with their external behaviors [17,18]. Known as the “benevolent faking” strategy [30], this method involves adjusting one’s internal emotional state to match the emotions expected by the organization, thus enabling more authentic and consistent emotional expressions [32]. This approach helps employees regulate their emotions more naturally, leading to improvements in job performance through genuine emotional expression.

This study explores the positive correlation between firefighters’ surface acting and job performance based on the CoR theory [33], which describes the active process through which individuals acquire, maintain, and protect the resources essential for their job performance [34]. It emphasizes the continual effort required to invest in resources to prevent potential losses, recover from past losses, and secure new resources [14]. Notably, the CoR theory acknowledges that the psychological impact of resource loss is generally more profound and sustained than the satisfaction gained from resource acquisition; as a result, the pain associated with resource loss often exceeds the pleasure derived from resource gains [35,36]. Negative emotional outcomes, such as burnout or job stress, typically arise in situations in which there is a threat of resource loss [37,38]. This is particularly evident when actual resource loss occurs or when the compensation for investment falls short of one’s expectations [39]. For instance, firefighters facing emotionally demanding situations often employ vital emotional resources such as affection or optimism, expecting appropriate compensation from their organization in return. If this compensation is perceived as insufficient to offset the expended emotional resources, it is viewed as a waste, potentially leading to negative impacts on job performance. Conversely, if the compensation adequately matches or exceeds the expended emotional resources, it is considered a net gain of resources, positively affecting job performance.

According to the CoR theory, the relationship between emotional labor and job performance may be profoundly influenced by the types of emotional regulation strategies employed, such as surface and deep acting [33,40]. Surface acting, which involves feigning emotions and suppressing one’s genuine emotions, requires considerable psychological effort and focus [16,17]. This intensive regulation not only consumes substantial cognitive resources but also results in a significant depletion of one’s emotional reserves [41]. The act of manipulating one’s emotional expressions through self-control can result in a comprehensive resource deficit [35]. Consequently, surface acting is associated with a loss of authenticity among firefighters, thus impeding the development of meaningful social relationships, increasing job dissatisfaction, and potentially diminishing job performance [33,42]. Moreover, it often leads to emotional dissonance—a misalignment between internal feelings and external expressions—further draining cognitive and motivational resources [35]. This depletion intensifies psychosocial risks such as burnout, exhaustion, and cynicism, which negatively impact work performance [43]. Conversely, deep acting, which entails aligning one’s emotions with those expected by the organization, is theorized to enhance job performance [33,40]. Firefighters who engage in deep acting experience public recognition and support for their authenticity, thereby boosting their sense of achievement and positively affecting their job outcomes [17]. Although it is more labor-intensive, deep acting helps reduce the discontinuity between one’s internal emotions and external actions, thus replenishing depleted resources and mitigating the negative emotional and psychological consequences of challenging work environments [44]. This approach not only preserves the well-being of firefighters but also improves their efficiency and effectiveness in fulfilling their duties.

Several studies have explored the relationship between emotional labor and job performance across various industries and countries. For instance, Kim et al. [45] found that among employees of private companies in South Korea, surface acting did not significantly impact job performance, whereas deep acting had a positive effect. Similarly, in their study on Dutch police officers, Van Gelderen et al. [46] discovered that surface acting was negatively associated with extra-role performance, while deep acting had a positive relationship with it. Additionally, Chen et al. [47] examined hotel employees in China and revealed that surface acting negatively affected perceived work performance, whereas deep acting positively influenced it. Based on these arguments and previous empirical evidence, we suggest the following hypotheses:

Hypothesis 1.

Surface acting is negatively related to job performance.

Hypothesis 2.

Deep acting is positively related to job performance.

2.2. Moderating Effects of Transactional and Transformational Leadership

The impact of emotional labor on job performance among firefighters may vary depending on the organizational context and conditions. Situational theorists argue that the link between employees’ work attitudes and performance may be contingent on the suitability of the human resource management practices within the specific context of the organization [48,49]. This perspective suggests that merely analyzing the relationship between emotional labor and job performance may not be sufficient to fully understand the mechanisms through which emotional labor affects organizational behavior. For example, previous studies have demonstrated that factors such as perceived organizational support [45], service training and mentoring [50], personality and gender [51,52], and emotional intelligence [53] can either amplify or diminish the effects of emotional labor. Therefore, it is necessary to consider various contextual factors within an organization to more thoroughly understand the impact of emotional labor on job performance.

In this study, we consider the continuous interactions between employees and their supervisors during job performance, wherein employees adjust their behaviors and values. We view the leadership styles of supervisors as a crucial situational factor that conditions the effects of surface and deep acting on job performance. Specifically, this research focuses on the potential moderating effects of transactional and transformational leadership, which have been widely studied in the field of public mental health [54].

Transactional leadership focuses on defining roles and task requirements and providing extrinsic rewards and punishments that are contingent on the fulfillment of contractual obligations [55]. This leadership style aligns followers’ self-interests with higher-order goals [56]. Bass [57] suggested that contingent rewards and management by exception are key job motivational factors within transactional leadership. First, transactional contingent rewards are crucial for effective leadership, as this approach involves establishing clear expectations and goals, thus motivating followers through rewards for goal attainment [58]. This involves a constructive exchange between leaders and followers, where tangible rewards are offered for fulfilling job responsibilities [59,60]. Second, in addition to positive reinforcement, transactional leaders employ management by exception as a form of negative reinforcement [61]. They address and punish deviations from contracts and standards, such as through pay reductions or termination when performance expectations are not met [56].

Transformational leadership involves making significant changes in the attitudes and assumptions of an organization’s members while fostering commitment to the organization’s missions, objectives, and strategies [55]. This leadership style focuses on actions that align followers’ needs and personal values with the organization’s goals [59]. Transformational leaders inspire their followers by setting ambitious visions and goals for the organization, thereby motivating them to find innovative solutions to problems. By fostering inspiration, motivation, and intellectual growth, these leaders help followers form an emotional commitment to the organization’s mission, resulting in increased loyalty [62]. Furthermore, transformational leaders act as ethical role models, prioritizing the organization’s interests over personal gain [63]. This idealized influence encourages followers to emulate their leaders and take pride in their association with the organization, thus reinforcing their sense of belonging and identification [60,61]. Finally, transformational leaders are crucial in maximizing their followers’ potential and addressing their individual needs and concerns. This personalized attention builds strong trust and loyalty toward leaders [64].

According to the JD-R theory, both transactional and transformational leadership styles may be crucial in managing job demands and the availability of job resources, which are key factors in improving job performance [23,24]. The JD-R theory posits that all occupations consist of two main categories of work characteristics: job demands and job resources [65,66]. Job demands are the physical, social, psychological, or organizational aspects of a job that require sustained physical or mental effort and can result in high work pressure and burnout [67]. In contrast, job resources are the physical, social, psychological, or organizational aspects that facilitate the achievement of work goals, reduce job demands, and promote personal growth [68]. Examples of job resources include performance feedback, participation in decision making, and organizational support for employees’ well-being [67]. According to the JD-R theory, high job demands lead to employee stress, resulting in exhaustion and decreased job performance [50]. However, various job resources can mitigate the negative effects of excessive job demands, counteracting the detrimental impact of emotional demands and job pressures. This balance between job demands and resources is crucial for maintaining employees’ well-being and performance [67].

Transactional leadership, as delineated by the JD-R theory, may play a crucial role in managing the balance of job resources and demands, which directly influences firefighters’ job performance. By setting clear expectations and implementing a system of rewards and penalties, transactional leaders can regulate the daily demands on employees and ensure these demands do not surpass the available resources, thereby maintaining a stable work environment and preventing resource depletion. Such leaders typically engage in management by exception, intervening only when standards are not met or when performance deviates from expected norms, which allows employees to efficiently utilize their job resources with minimal oversight and supports the JD-R model’s emphasis on an optimal balance between job demands and resources [69]. This focus on corrective actions and contingent rewards motivates employees to effectively manage their demands [70]. Furthermore, the predictable and structured approach of transactional leadership helps employees, such as firefighters in high-pressure environments, to better allocate their mental and physical resources, thus reducing the cognitive and emotional labor required in decision making under stress and weakening the negative impact of emotional labor on job performance.

Transformational leaders excel by presenting a vision that is not only achievable but also conducive to fresh opportunities, in alignment with the JD-R theory, which conceptualizes such visions as potent motivators that energize employees [24]. They tailor their approach by providing feedback, coaching, and advice that match the individual skills of each employee while also recognizing their contributions. This approach not only creates a positive work atmosphere but also augments employees’ emotional energy, effectively addressing the JD-R model’s focus on balancing job demands with sufficient resources [23,71]. Additionally, transformational leadership empowers subordinates and clarifies goals, driving intellectual growth and encouraging employees to approach challenges innovatively and develop creative solutions [72]. This method of leadership is particularly effective in terms of increasing employees’ willingness to acquire and adapt new skills and knowledge. For example, firefighters who perceive their leaders as genuinely empathetic and supportive are better equipped to offset the resource depletion that accompanies surface acting and manage intense job demands, thus enhancing their job performance [69]. This suggests that transformational leadership can shape firefighters who engage in surface acting into resilient, emotionally stable individuals. Similarly, firefighters practicing deep acting under transformational leadership may experience an upsurge in their willpower and psychological strength, enhancing their commitment to deep acting during emotionally demanding interactions and promoting excellence in their roles. Consequently, transformational leadership plays a crucial role in motivating firefighters who employ deep acting techniques, thereby improving their job performance.

While there is a theoretical basis for the moderating impact of transactional and transformational leadership on the relationship between emotional labor and job performance, empirical evidence regarding this matter remains sparse. Many studies have investigated the roles of perceived organizational support, psychological capital, gender, and personality within the context of emotional labor and its outcomes at work. However, the specific effects of transactional and transformational leadership in mitigating the adverse outcomes associated with emotional labor, particularly in relation to surface and deep acting, are not well documented. This lack of empirical data highlights the need for focused research concerning how these leadership styles can counter the negative impacts of emotional labor and enhance employee performance. Thus, we suggest the following research hypotheses:

Hypothesis 3.

Transactional leadership moderates the negative relationship between surface acting and job performance, such that this relationship is much weaker when transactional leadership is higher rather than lower.

Hypothesis 4.

Transactional leadership moderates the positive relationship between deep acting and job performance, such that this relationship is much stronger when transactional leadership is higher rather than lower.

Hypothesis 5.

Transformational leadership moderates the negative relationship between surface acting and job performance, such that this relationship much is weaker when transformational leadership is higher rather than lower.

Hypothesis 6.

Transformational leadership moderates the positive relationship between deep acting and job performance, such that this relationship is much stronger when transformational leadership is higher rather than lower.

3. Model Specification

3.1. Research Model

The research model employed in this study visualizes how transactional and transformational leadership styles moderate the relationship between emotional labor—specifically, surface and deep acting—and job performance among firefighters, integrating the CoR and JD-R theories (see Figure 1). According to the CoR theory, surface acting depletes emotional resources, negatively impacting job performance (Hypothesis 1: H1), while deep acting conserves and replenishes resources, positively affecting performance (Hypothesis 2: H2). The JD-R theory suggests that transactional leadership, with its emphasis on clear expectations and contingent rewards, can alleviate the negative effects of surface acting (Hypothesis 3: H3) and enhance the benefits of deep acting (Hypothesis 4: H4). Conversely, transformational leadership, which emphasizes inspiration and motivation, is expected to reduce the harmful impact of surface acting (Hypothesis 5: H5) and further strengthen the positive influence of deep acting on job performance (Hypothesis 6: H6). These hypotheses highlight the critical role of leadership in managing job demands and resources in the high-stress environments faced by firefighters in South Korea.

3.2. Data Sources and Sample

In this study, survey data were collected from firefighters in Gyeonggi-do, South Korea’s most populous province (Gyeonggi-do, South Korea, encircling the capital city of Seoul, plays a pivotal role in the country’s administration and economy due to its strategic location and large population. According to the most recent estimates, Gyeonggi-do has a population of over 13 million people, solidifying it as a central hub for both economic activity and administrative importance). These individuals are civil servants who have successfully passed civil service examinations and are employed under the national government’s oversight. The province hosts 9686 street-level firefighters distributed across 35 fire stations, whose primary responsibilities include extinguishing fires and conducting rescue operations. The organizational structure places these firefighters within a seven-tier job-grade hierarchy, ranging from firefighter (Grade 1) to fire chief (Grade 7), with their responsibilities increasing significantly at each level. For instance, while entry-level firefighters are primarily involved in direct firefighting and rescue efforts, those with higher grades manage fire station operations, including training, performance evaluation, and the allocation of duties.

To enhance the external validity of the study’s results, a quota sampling method based on job grades was implemented to ensure representative sampling from each grade. However, this method did not fully capture the broader demographic diversity of the firefighter population in Gyeonggi-do, such as differences in gender and educational backgrounds. The survey was administered via email from 6 April to 17 April 2020. After invalid responses were discarded, including those with repetitive answers or excessive missing data, a total of 1578 valid responses were retained, yielding a response rate of 16.27%. All survey questions, except for demographic queries, were assessed using a Likert scale ranging from 1 (strongly disagree or very unlikely) to 5 (strongly agree or very likely).

3.3. Measures

3.3.1. Dependent Variable

The dependent variable was job performance. Job performance refers to the extent to which an organizational member’s job is successfully accomplished, and it can be regarded as generally aligning with the meaning of productivity as employed by industrial psychologists [73]. Job performance is a qualitative or quantitative outcome achieved by an employee or organization, and it can be described as a resultant goal that managers strive to influence by judging the effectiveness of an individual, group, or organization [74]. Four items were used to measure job performance: (1) “I faithfully fulfill the duties and responsibilities assigned to me;” (2) “I fulfill the responsibilities included in my job description;” (3) “I do not neglect any work required to perform my job;” (4) “I meet the performance standards required of me.” These items were specifically designed to comprehensively capture various aspects of job performance within the context of public sector organizations, where task completion, adherence to job responsibilities, and compliance with overall work standards are critical [75]. The basis for these questions is grounded in established frameworks from the performance management literature, which highlight task performance, role fulfillment, and adherence to performance standards as essential indicators of job performance in public sector settings [76]. Each question was carefully crafted to represent these critical dimensions, ensuring that the responses accurately reflect the respondent’s effectiveness and commitment to their role.

3.3.2. Independent Variables

The independent variable in this study was emotional labor, which Hochschild [25] and Grandey [12] classified as either surface acting or deep acting. Surface acting is evident when employees express false emotions to others and act in a way that belies their actual emotions. Conversely, deep acting is measured by employees’ efforts to express emotions appropriate to the job and to actually feel the emotions they are supposed to express [36]. In this study, surface acting was encapsulated by the following statements: (1) “I am reluctant to express my true feelings”; (2) “I act out emotions I do not feel”; (3) “I hide my true feelings in certain situations”. Conversely, the following statements coincide with deep acting: (4) “I make an effort to actually feel the emotions I should express to others”; (5) “I try to actually experience the emotions I am supposed to show”; (6) “I try to actually feel the emotions I am supposed to express as part of my job”.

3.3.3. Moderating Variables

In this study, transactional leadership and transformational leadership were used as moderating variables to examine whether they influence the relationships between the two types of emotional labor and job performance. Transactional leadership emphasizes clearly defining roles and task requirements while providing external rewards and punishments based on the fulfillment of contractual obligations [55]. In this study, the following three items were used to measure transactional leadership [77]: (1) “My manager gives positive feedback to subordinates who perform well”; (2) “My manager actively expresses appreciation to subordinates who perform above expectations”; (3) “My manager personally praises subordinates who perform well”. These items are directly reflective of transactional leadership’s emphasis on reward-based motivation and clear communication of expectations, ensuring their effectiveness in capturing the essence of this leadership style.

Transformational leadership influences subordinates to perform beyond their capabilities by satisfying higher-order needs beyond personal interests. The following five items were constructed and utilized to measure transformational leadership [78]: (1) “My boss clearly articulates his/her vision”; (2) “My boss leads by example”; (3) “My boss inspires me to approach things in a new way”; (4) “My boss makes people feel proud to be part of the organization”; (5) “My boss has a clear idea of where the organization should be in the next five years”. These items were chosen because they encapsulate the motivational and visionary aspects of transformational leadership, which are critical for driving organizational change and encouraging innovative thinking among subordinates.

3.3.4. Controls

Based on prior research, the control variables used to study the impact of emotional labor on job performance included demographic factors. The variables included were gender, coded as 1 for female and 0 for male; age categories, with 1 representing 20–29 years old, 2 for 30–39 years old, 3 for 40–49 years old, and 4 for those 50 years old and older; educational level, coded as 1 for high school, 2 for college, 3 for a bachelor’s degree, and 4 for graduate school; job grade, ranging from 1 for Grade 1 to 7 for Grade 7; length of tenure, coded as 1 for less than nine years, 2 for 10–19 years, 3 for 20–29 years, and 4 for more than 30 years; and annual income, coded from 1 for USD 30,000 to 10 for USD 100,000. Additionally, job satisfaction was included as a significant predictor of employee job performance [79]. The following five items were constructed and utilized to measure job satisfaction: (1) “I am very satisfied with my job”; (2) “I am satisfied with my job at the moment”; (3) “I usually work hard at my job”; (4) “My job is better than other coworkers’ work”; (5) “I enjoy my job”.

Table 1. Descriptive statistics.

Variable	Mean	S.D.	Min	Max
Job performance	4.060	0.608	1	5
Surface acting	2.472	0.796	1	5
Deep acting	2.829	0.822	1	5
Transactional leadership	3.833	0.710	1	5
Transformational leadership	3.606	0.701	1	5
Job satisfaction	3.948	0.666	1	5
Gender	0.135	0.341	0	1
Age	2.341	0.967	1	4
Education	2.319	0.825	1	4
Job grade	2.655	1.401	1	7
Tenure	1.594	0.802	1	4
Annual income	3.849	2.209	1	10

Note: S.D. = standard deviation.

indicates the descriptive statistics of the variables used in this study.

3.4. Measurement Reliability and Validity

To evaluate the reliability of our measures, a confirmatory factor analysis was conducted using structural equation modeling (SEM). The results, presented in

Table 2. Results of confirmatory factor analyses.

Model	${\mathit{\chi }}^2$	df	RMSEA	CFI	TLI	SRMR
Six-factor model	1096.07 ***	215	0.05	0.97	0.97	0.03
Five-factor model (JS and JP combined)	5304.94 ***	220	0.12	0.83	0.8	0.08
Four-factor model (JS, JP, and TAL combined)	10,220.92 ***	224	0.17	0.66	0.61	0.12
Three-factor model (JS, JP, TAL, and TFL combined)	11,508.25 ***	227	0.18	0.62	0.57	0.14
Two-factor model (JS, JP, TAL, TFL, and DA combined)	14,493.36 ***	229	0.20	0.51	0.46	0.16
One-factor model	16,241.51 ***	230	0.21	0.45	0.4	0.17

Note: *** p < 0.01.; df = degree of freedom; JS = job satisfaction; JP = job performance; TAL = transactional leadership; TFL = transformational leadership; DA = deep acting.

, indicate that the proposed six-factor measurement model (job performance, transactional leadership, transformational leadership, job satisfaction, surface acting, and deep acting) fits the data well. Specifically, the root mean square error of approximation (RMSEA) and standardized root mean square residual (SRMR) were both within acceptable limits, at 0.05 and 0.03, respectively, which is well below the 0.08 threshold. The comparative fit index (CFI) and Tucker–Lewis Index (TLI) both scored 0.97, surpassing the generally recommended level of 0.9. These metrics support the validity of using separate measures for each of the four latent variables. Furthermore, composite reliabilities for all latent variables were calculated using Cronbach’s alpha, with coefficients ranging from 0.85 to 0.95, thus exceeding the commonly recommended 0.70 threshold. To mitigate concerns about common method variance (CMV), which could potentially exaggerate the relationships between variables derived from the same data source, Harman’s single-factor test was conducted. The principal explanatory factor explained only 38% of the covariance among the measures, well below the 50% threshold, suggesting that CMV is unlikely to significantly impact the observed relationships in this study.

4. Findings

In this study, a hierarchical ordinary least squares regression analysis was conducted using STATA 17.0 to explore the impact of firefighters’ emotional labor on job performance and to empirically analyze the moderating effects of transactional and transformational leadership. Specifically, Model 1 examined the effects of control variables such as age, tenure, and educational background on job performance. Model 2 explored the main effects of independent variables such as surface acting and deep acting on job performance. Finally, Model 3 investigated the moderating effects of transactional and transformational leadership, incorporating the following interaction terms: surface acting × transactional leadership, deep acting × transactional leadership, surface acting × transformational leadership, and deep acting × transformational leadership. The results of these analyses are presented in

Table 3. Hierarchical ordinary least squares regression analysis of the impact of emotional labor on job performance.

	Model 1		Model 2		Model 3
	β	S.E.	β	S.E.	β	S.E.
Gender (female = 1)	–0.010	0.039	–0.007	0.038	−0.005	0.038
Age	0.040	0.025	0.032	0.020	0.029	0.024
Education	0.034 **	0.016	0.034 **	0.016	0.034 **	0.016
Job grade	0.033 *	0.019	0.030	0.019	0.028	0.019
Tenure	–0.045	0.033	–0.040	0.033	–0.035	0.032
Annual income	–0.002	0.007	–0.004	0.007	–0.001	0.007
Job satisfaction	0.317 ***	0.031	0.283 ***	0.031	0.284 ***	0.030
Transactional leadership (TAL)	0.101 ***	0.034	0.093 ***	0.034	0.096	0.171
Transformational leadership (TFL)	0.124 ***	0.038	0.101 ***	0.037	0.229	0.175
Surface acting (SA)			–0.125 ***	0.021	0.070	0.109
Deep acting (DA)			0.006	0.017	0.018	0.103
TAL × SA					0.075 *	0.044
TAL × DA					–0.072 *	0.041
TFL × SA					–0.132 ***	0.045
TFL × DA					0.072 *	0.039
Constant	1.797 ***	0.118	2.354 ***	0.164	1.860 ***	0.416
R-squared	0.265		0.287		0.295

Note: * $p$ < 0.1; ** $p$ < 0.05; *** $p$ < 0.01.; S.E. = robust standard error; N = 1444.

.

First, the results from Model 1 analyzing the impact of control variables on job performance suggest that education ($\beta$ = 0.034, $p$ < 0.05), job grade ($\beta$ = 0.033, $p$ < 0.010), and job satisfaction ($\beta$ = 0.317, $p$ < 0.01) significantly influence job performance. Specifically, a higher education level and higher job grade positively affect job performance, and greater job satisfaction enhances job performance, in alignment with findings from previous studies [79]. Conversely, demographic variables such as gender, age, tenure, and total income do not significantly impact job performance.

The findings also indicate that both transactional ($\beta$ = 0.101, $p$ < 0.01) and transformational leadership ($\beta$ = 0.124, $p$ < 0.01) positively impact job performance. Transactional leadership, with its emphasis on clear expectations and the contingent reward system, ensures that employees have precise guidelines and incentives to meet specific objectives efficiently [56]. This structure directly influences the consistency and quality of job performance. Conversely, transformational leadership enhances performance by inspiring employees, thus fostering an environment that encourages innovation and aligning the organization’s goals with employees’ personal values [61]. This leadership style not only motivates employees but also fosters a deeper commitment to their tasks, leading to enhanced performance levels [80].

Model 2 confirmed Hypothesis 1 by demonstrating that surface acting, a component of emotional labor, has a direct negative effect on job performance ($\beta$ = –0.125, $p$ < 0.01). This finding is consistent with prior research that identifies surface acting as a potential source of emotional dissonance, which adversely affects performance [46,47]. According to the CoR theory, surface acting is particularly detrimental because it involves displaying emotions that are incongruent with genuine feelings, leading to psychological strain. This strain is not merely a temporary discomfort but results in a significant depletion of emotional and cognitive resources. This depletion, in turn, escalates stress and diminishes job performance, as employees expend considerable effort in masking their true emotions without resolving the underlying affective experience. This ongoing dissonance can precipitate burnout, further undermining job effectiveness.

Hypothesis 2 was rejected due to the absence of a statistically significant relationship between deep acting and job performance (no β reported, p > 0.10). Deep acting involves an authentic alignment of internal feelings with external expressions, which theoretically should conserve emotional resources better than surface acting. This conservation stems from the genuine processing of emotions, which avoids the psychological tax of suppression or fabrication and thereby reduces the risk of emotional exhaustion. This preservation of personal resources is crucial in mitigating the negative impacts typically associated with emotional labor [28]. However, the neutral outcome in our findings suggests that while deep acting may prevent resource depletion, it does not necessarily translate into enhanced job performance. This may be due to the complex dynamics involved in managing authentic emotional adjustments, which, although less taxing, still require effort and may not directly improve job outcomes. The lack of significant enhancement in performance could reflect an equilibrium where the conservation of resources simply stabilizes performance rather than elevating it.

Model 3 examined the moderating effects of transactional and transformational leadership on the relationships between the two forms of emotional labor and job performance, incorporating interaction terms to assess these dynamics. Hypothesis 3 was supported, as the analysis revealed that transactional leadership significantly moderated the relationship between surface acting and job performance ($\beta$ = 0.075, $p$ < 0.10). Specifically, while surface acting generally exerted a negative impact on job performance, higher levels of transactional leadership were found to mitigate this effect. This mitigation occurs because transactional leadership, with its clear expectations and structured reward systems, provides a framework within which employees can better manage the emotional dissonance caused by surface acting. This structured approach reduces the psychological toll of maintaining emotional inconsistencies, thereby lessening the negative impact on job performance.

Conversely, Hypothesis 4 was rejected, as the results indicated that transactional leadership had a deleterious effect on the relationship between deep acting and job performance (β = −0.072, p < 0.10). Deep acting typically enhances job performance through genuine emotional engagement. However, the emphasis on explicit rewards and penalties in transactional leadership may stifle the intrinsic motivations essential for effective deep acting. By prioritizing external rewards over authentic emotional expression, transactional leadership can undermine the benefits that deep acting offers, such as enhanced emotional well-being and reduced exhaustion. This misalignment with the core principles of deep acting can lead to reduced effectiveness in improving job performance, as the genuine emotional connections necessary for optimal performance are de-emphasized.

Figure 2 and Figure 3 provide a detailed visualization of the marginal effects of surface acting and deep acting on job performance with varying levels of transactional leadership. As anticipated, Figure 2 demonstrates that the detrimental link between surface acting and the job performance of firefighters is notably diminished under high transactional leadership, marked as one standard deviation (S.D.) above the mean (blue solid line). In contrast, this negative relationship intensifies under low transactional leadership, which is one S.D. below the mean (red dotted line). In contrast to our expectations, Figure 3 illustrates that compared with high transactional leadership levels, low transactional leadership levels more significantly enhance the positive association of deep acting with job performance.

Figure 4 and Figure 5 illustrate how the effects of surface acting and deep acting on job performance vary with different levels of transformational leadership. In Figure 4, the blue line for high transformational leadership is characterized by a steeper downward slope, suggesting that as surface acting increases, job performance declines more sharply under high transformational leadership compared to lower levels. Meanwhile, Figure 5 presents a blue line representing high transformational leadership that exhibits a steeper upward slope, indicating that as deep acting increases, job performance significantly improves under strong transformational leadership.

Consequently, Hypothesis 5 was rejected, as transformational leadership demonstrated a statistically significant moderating effect ($\beta$ = –0.132, $p$ < 0.01) that intensified the negative relationship between surface acting and job performance. This indicates that surface acting adversely affects job performance, and higher levels of transformational leadership amplify this negative impact, resulting in poorer job performance. Conversely, Hypothesis 6 was accepted because transformational leadership exhibited a statistically significant moderating effect ($\beta$ = 0.072, $p$ < 0.10) that reinforced the positive relationship between deep acting and job performance. This suggests that deep acting positively influences job performance, and a higher degree of transformational leadership intensifies this positive impact, leading to enhanced job performance.

According to the JD-R theory, it is plausible that transformational leadership strengthens the negative relationship between surface acting and job performance because surface acting is a job demand that drains employees’ emotional resources. Transformational leadership, which emphasizes high expectations and emotional involvement, can exacerbate the stress and emotional dissonance associated with surface acting, resulting in further declines in job performance [81]. In contrast, transformational leadership enhances the positive relationship between deep acting and job performance because deep acting aligns with the job resources component of the JD-R theory. Transformational leaders provide support, inspiration, and a sense of purpose, which helps employees manage their emotions more authentically and effectively. This supportive environment facilitates deep acting, thereby improving job performance by promoting genuine emotional engagement and reducing emotional exhaustion [24].

5. Discussion and Implications

Our research, based on the CoR theory, examines the effects of surface and deep acting on the job performance of firefighters in South Korea. Specifically, this study builds on the JD-R theory by examining how transactional and transformational leadership moderate the effects of these two forms of emotional labor on the job performance of firefighters, a topic that has received relatively little attention in previous research. Therefore, this study makes a theoretical and practical contribution by addressing a gap in public organization management research.

5.1. Theoretical Implications

This study highlights significant theoretical implications related to the impact of emotional labor strategies on job performance in high-stress professions, specifically among firefighters. In alignment with the COR theory, the findings underscore that surface acting, which is characterized by a misalignment between felt and expressed emotions, depletes cognitive and motivational resources, leading to increased stress, burnout, and ultimately, diminished job performance. This degradation is exacerbated by a lack of authentic social interactions, which further erodes job satisfaction and emotional engagement.

Conversely, the study suggests that deep acting, which involves aligning one’s internal feelings with one’s external expressions through genuine emotional processing, does not significantly deplete emotional resources. This suggests that deep acting may help preserve personal resources, potentially reducing emotional exhaustion. However, the absence of a significant positive impact on job performance indicates that while deep acting might prevent resource loss more effectively than surface acting, this does not necessarily translate into improved performance outcomes. This could be attributed to the complexities and demands of managing authentic emotional expressions in the unpredictable and high-stress scenarios faced by firefighters. Consequently, while deep acting conserves resources better than surface acting, it does not necessarily translate into improved performance outcomes. This aspect of the findings prompts a nuanced interpretation of the CoR theory, emphasizing the need to consider both resource preservation and the complexities of how these resources interact with job demands in high-stress environments.

The findings of this study offer profound insights into the theoretical implications of the JD-R theory, particularly in the context of how leadership styles interact with emotional labor strategies to affect job performance. The evidence underscores a nuanced application of the JD-R theory in workplace settings, emphasizing the complex interplay between job demands, resources, and leadership. For instance, our study reveals that transactional leadership can enhance the relationship between surface acting and job performance. This leadership style, with its focus on clear guidelines, rewards, and corrective actions, serves as a job resource by mitigating the stress associated with surface acting. The structured environment provided by transactional leadership reduces the taxing nature of emotional labor, enabling employees to perform better despite the emotional dissonance typically associated with surface acting. Conversely, transformational leadership amplifies the challenges posed by surface acting. By heightening emotional involvement and expectations, transformational leadership increases the strain induced by the emotional dissonance of surface acting, thus exacerbating its negative impact on job performance. However, transformational leadership positively affects the relationship between deep acting and job performance. Since deep acting aligns more closely with job resources—facilitating genuine emotional expression and alignment—transformational leaders enhance this alignment by fostering a supportive and inspirational environment. This support not only enables but actively promotes deeper emotional engagement and reduces exhaustion, leading to improved job performance.

These findings illustrate the JD-R theory’s applicability in differentiating how various leadership styles can act as either demands or resources, depending on the emotional labor involved. Transactional leadership, which is typically regarded as less favorable in modern discussions on leadership, can be quite beneficial in contexts in which employees must engage in surface acting by providing the necessary structure to cope with its demands. Transformational leadership, while generally viewed positively, can exacerbate the demands of surface acting due to its emphasis on high emotional engagement. However, it is exceptionally beneficial for deep acting scenarios, where authenticity and emotional alignment are crucial.

Accordingly, our research not only confirms the relevance of the JD-R theory in analyzing workplace dynamics but also enriches our understanding of how specific leadership styles can be strategically aligned with emotional labor practices to improve a firefighter’s job performance. This perspective invites further explorations into how to tailor leadership development programs that consider the specific emotional demands of different roles and industries, thereby maximizing the potential benefits of each leadership style within the JD-R framework.

5.2. Practical Implications

This study offers some important implications for practice. First, firefighting organizations can strategically enhance job performance by applying transactional leadership to manage surface acting effectively. This leadership style, with its emphasis on clear guidelines and rewards, provides a structured environment that can help mitigate the stress associated with emotional labor. By offering clear expectations and immediate feedback, transactional leadership enables firefighters to maintain their performance levels despite the emotional dissonance that surface acting can evoke, thus ensuring that they can focus on their tasks without being overwhelmed by emotional demands and ultimately leading to improved job performance and reduced stress. To support this implementation, policymakers should mandate leadership training programs emphasizing transactional techniques, including setting clear expectations, providing consistent feedback, and establishing a rewards system. Additionally, organizations should create policies for regular evaluations and feedback mechanisms to ensure the consistent application of transactional leadership practices. Allocating resources for continuous professional development and establishing clear, standardized procedures will further institutionalize transactional leadership, thus fostering an environment in which firefighters can thrive despite the emotional demands of their work.

Transformational leadership should be leveraged to promote deep acting, which aligns closely with firefighters’ need for authenticity in high-stress scenarios. This leadership style enhances emotional alignment and genuine expression, which are critical in deep acting situations, where firefighters must manage their internal emotions to match their external actions. To implement this, fire departments should develop comprehensive training programs focused on transformational leadership skills, such as empathy, inspirational motivation, and intellectual stimulation. Leaders should foster a supportive environment that encourages open communication and genuine emotional expression, provide emotional support during and after critical incidents, and recognize early signs of emotional fatigue. Regular debriefing sessions following intense operations can also help reduce exhaustion and improve overall job performance by allowing firefighters to discuss their experiences and emotions in a structured yet supportive setting.

Firefighting organizations should develop specialized leadership training programs tailored to the unique emotional and psychological demands of the profession. These programs should focus on enhancing a range of leadership skills aligned with the diverse emotional labor challenges firefighters face. Training could focus on transactional leadership techniques to ensure a clear organizational structure and compliance with established protocols, as well as on transformational leadership skills to foster emotional support and motivation among employees. The programs should also feature modules about recognizing and responding to different scenarios involving emotional labor, such as managing stress in high-risk operations and building resilience after traumatic events, incorporating practical exercises and simulations for hands-on applications. By customizing these programs to the specific needs of firefighting tasks, firefighting organizations can ensure that leaders are prepared to manage both tactical and emotional challenges, thus enhancing the well-being of firefighters and the overall effectiveness of operations in high-stress environments.

5.3. Limitations and Future Research

The limitations of this study provide valuable directions for future research. First, this study utilized a cross-sectional self-report survey and subjective measures, which could lead to CMV. Although Harman’s single-factor test indicated minimal CMV concerns, future research should employ more objective measures and longitudinal data to enhance the accuracy of causal inference. Second, while this study used well-established items to measure job performance, transactional leadership, and transformational leadership, it is important to acknowledge that these items may not fully capture the complexity and nuances of these constructs. Future research should focus on developing and validating more precise measurement instruments that can more accurately reflect the underlying dimensions of these concepts. Third, this study is limited in its data collection solely targeting Gyeonggi province, which may not represent the broader demographic and regional variations of firefighters across South Korea. Future research should consider a wider geographical area to enhance representativeness, both within South Korea and internationally. Expanding the scope to include firefighters from other countries could provide valuable comparative insights and help address the diverse conditions and needs of firefighters in different global regions through comparative and longitudinal studies. Fourth, utilizing latent variable modeling techniques, such as SEM and item response modeling, could help to better estimate the relationships between latent constructs, such as emotional labor types, transactional and transformational leadership, and job performance. Unlike OLS regression, partial least squares SEM can accommodate measurement errors and simultaneously model various endogenous constructs. Fifth, future research should also investigate the association between firefighters’ emotional labor and important work-related outcomes, including organizational citizenship behavior, performance, burnout, and insomnia. This exploration could help deepen our understanding of surface and deep acting within public health management. Another important research avenue involves considering confounding factors that might directly affect job performance or interact with emotional labor, such as psychological capital, organizational climate, psychological empowerment, and person–organization fit. These factors are crucial for fully interpreting the findings of our study. Finally, the external validity of our study is constrained because all participants were firefighters from South Korea. To broaden these findings, future research should encompass diverse industries such as hospitality, tourism, airlines, and police work.

5.4. Conclusions

This study enhances the understanding of the dynamics between emotional labor and job performance within the firefighting profession, emphasizing the differential impacts of surface and deep acting moderated by transactional and transformational leadership styles. Theoretically, it validates and extends the JD-R model by illustrating how specific leadership behaviors can either mitigate or amplify the psychological costs associated with emotional labor. With regard to practice, the findings advocate for tailored leadership development programs that align with the unique emotional burdens faced by firefighters, promoting strategies that support psychological well-being and performance efficacy. This research not only contributes to academic discourse but also informs policymakers on structuring more effective human resource strategies in public safety sectors, suggesting a need for broader, more diverse investigations to reinforce these conclusions globally.