Human resources management (HRM) has emerged as a critical trend in contemporary organizations, playing a pivotal role in ensuring the organization’s success through the establishment of practices and guidelines that effectively manage employees throughout various stages, encompassing pre-hiring, post-hiring, and at employee termination [1]. Establishing such effective guidelines will not only provide a clear direction for employees but also yield a positive organizational impact as a whole. HRM practices within an organization exert a positive impact on job performance through variables such as selection, participation, and employee empowerment ^[2][3][2,3]. These dimensions enable us to link HRM with sustainability, thereby contributing to long-term performance and efficiency [1].

The concept of sustainable HRM underscores the significant role of HR policies in aligning with the ultimate objectives of organizations, particularly those that extend beyond mere profit generation ^[4][5][4,5]. Prior research has demonstrated a consistent and positively linear relationship between HRM policies and job performance ^[6][7][8][6,7,8]. Moreover, HRM policies demonstrated an overall positive relationship with the productivity of an organization ^[9][10][11][9,10,11]. When HRM policies are implemented and standardized within an organization, all members of the organization tend to have increased confidence that their treatment and job conditions are equitable and fair [12]. As a result, sustainable HRM is perceived as the imperative choice if conventional HR concepts are to maintain their relevance in the ever-evolving business landscape for the foreseeable future.

Recent studies have presented statistical evidence demonstrating the association between sustainable HRM and its positive influence on employee performance, e.g., ^[13][14][13,14]. However, the existing literature, i.e., [13], proposed that future studies should explore other organization-level boundary conditions (e.g., leadership) to gain a more comprehensive understanding of how HRM practices impact employee well-being and performance. T

As previously discussed, the concept of sustainable HRM encompasses the internal dynamics of an organization that contribute to its prolonged viability and prosperity. Furthermore, it can encompass outcomes that extend beyond the organization itself, encompassing benefits for the broader society in which the organization operates, as well as the environmental dimension ^[15][16]. Sustainability in HRM offers practical solutions for attracting and retaining dependable, trustworthy, and highly skilled employees for businesses aiming to promote their brand among both their current workforce and potential prospective candidates ^{[16][17][18][19]}[17,18,19,20]. Consequently, it is recommended that organizations integrate sustainability into their HRM practices not solely for the purpose of enhancing their image as employers or organizations but also to distinguish themselves from competitors within the job market and enhance their attractiveness to prospective employees. Previous studies have highlighted the positive impact of sustainable HRM practices on employees’ job performance by improving their motivation, attitudes, and behaviors. This, in turn, contributes to enhanced organizational performance as well as individual job performance ^{[1][7][8][11]}[1,7,8,11]. The research has highlighted the crucial role of leadership in enhancing employee satisfaction by creating favorable conditions (e.g., initiatives) to promote growth, development, a sense of belonging, autonomy, and meaningful work. Employees with positive attitudes are often motivated to exert maximum effort with the expectation of earning a promotion within the organization ^[20][21][21,22]. Lu et al. [13] argued that contribution of sustainable HRM practice on employee performance is attributed to the positive impact of sustainable HRM practices on employee resilience and work engagement, which indirectly results in increased employee job performance. Contrary to its numerous benefits, which include elevating the standards of living for employees, some studies have adopted a contrasting perspective. They emphasize the potential negative impacts of sustainable HRM on employee health, which can impede both their professional development and personal growth, particularly through the implementation of high-performance work systems ^[22][23].

The Ability–Motivation–Opportunity (AMO) framework emphasizes that sustainable HRM practices have the potential to impact employee performance and productivity ^[23][24]. The AMO theory underscores that sustainable HRM practices motivate employees to achieve objectives by leveraging their own knowledge, skills, and abilities ^{[24][25][26][27]}[25,26,27,28]. According to the AMO theory, when employees are motivated to engage in their job and perceive their work as meaningful and valuable, they are more likely to exhibit high levels of performance ^[28][29]. Concisely, sustainable HRM practices should offer incentives that motivate employees to excel and recognize the impact they make on society and the organization. Therefore, sustainable HRM practices encourage employees to perform well, and this high performance can contribute to organizational sustainability. Furthermore, motivated employees may take the initiative to establish proactive work dynamics that add additional value to the implementation of sustainability within the organization ^[29][30]. If employees perceive HRM procedures as elements that contribute to their own sense of worth or value, they tend to be more inclined to reciprocate by contributing something valuable in return. In such a scenario, when employees view such signals in HRM as demonstrating compliance, openness, and consistency, they are more likely to exhibit a willingness to take on additional roles within the organization. This often results in the display of positive attitudes and actions, particularly when it comes to fostering creativity and productivity in the workplace ^[28][29].

2.2. Sustainable HRM and Trust in Leaders

Sustainable HRM can be delineated from mainstream HRM by virtue of distinct attributes, including flexibility, employee participation, value orientation, knowledge orientation, competency, stakeholder orientation, and a mutually trusting relationship between employees and leaders ^[19][30][15,20]. Therefore, this underscores the importance of organizations considering that the implementation of sustainable HRM practices must be accompanied by the cultivation of a trusting relationship between employees and their leaders. This dynamic facilitates employee development and growth while also ensuring the enduring success of sustainable HRM practices in the long term [31]. It has been posited that, in order to achieve success, organizations must undertake multifaceted transformations. This endeavor requires concerted efforts in strategically implementing sustainable plans, perspectives, and procedures, spanning both the internal and intra-organizational dimensions of the company (i.e., creative cultural atmosphere, easygoing configurations, and clear paths of communication that lack ambiguity) ^[32][33][32,33]. Sustainable HRM endeavors to establish a creative cultural atmosphere by fostering employees’ innovative potential and implementing impartial systems. This includes fostering new ideas in technology, distributing power equitably, and enabling employees to communicate freely with others in the organization, irrespective of hierarchical positions ^[34][35][34,35]. Accordingly, one of the main goals of SHRM is to implement environmentally friendly processes and simultaneously assess their subsequent implications on the organizational environment. When making decisions about implementing sustainable HRM practices within an organization, it is essential to consider three key factors: equity, employee well-being, and professional development. These elements collectively contribute to the development of better relationships between employees and leaders within the organization. In light of these findings, it is evident that, when an organization intends to implement sustainable HRM practices, it must place significant emphasis on cultivating a trusting relationship between employees and their leaders. Such trust serves as a foundational element, creating an environment conducive to employee development and growth, ultimately facilitating the successful adoption of sustainable HRM practices with a long-term perspective ^[19][36][20,36].

2.3. Trust in Leaders and Job Performance

Jones et al. established a distinction between leadership and a leader in their study. They posited that leadership involves the interpersonal processes related to behaviors like acting as a leader during work, demonstrating interpersonal skills, and motivating the team to achieve common goals. Conversely, a leader is someone who proficiently engages in certain behaviors, along with possessing traits and other personal attributes, such as skills and experience, that enable them to effectively demonstrate leadership actions. Holmes and Rempel [37] delved into the idea that trust in a leader fosters an environment where employees feel emboldened to voice their opinions and take proactive initiative within the organization. Their argument centered on the premise that such behaviors emerge from a foundation of trust, signifying that the leader will not purposefully provide detrimental feedback, act with self-interest, or exploit the employees. Hence, having trust in the leader motivates employees to exhibit greater proactivity and instils in them a sense of security and recognition, ultimately manifesting in their individual job performance. Numerous prior studies have consistently shown that a supportive leader has a positive impact on work attitudes and performance, particularly in fostering creativity and innovation ^{[38][39][40][41][42]}[38,39,40,41,42]. Studies have also emphasized the significant role of effective leadership in enhancing employees’ work performance by efficiently managing factors such as work intervention, civility, respect, and work engagement ^{[13][43][44][45]}[13,43,44,45]. Their findings confirmed that the implementation of such practices can foster organizational sustainability by promoting extensive enhancements in employees’ psychological capital, job satisfaction, performance, and reducing burnout and turnover. In this regard, Corbos et al. [46] correspondingly found that an efficient leadership style (i.e., transformational and transactional) would impose prolonged advantages on the workplace. This positively impacts the quality of employees’ performance and their perception of interpersonal relationships in the workplace. The primary focus of these studies underscores the significance of leaders in promoting positive outcomes within the context of sustainable HRM ^[47][48][47,48]. Consequently, when employees perceive their perspectives as valuable and influential within their group, organizations can effectively foster a culture of creative conduct ^{[49][50][51][52][53]}[49,50,51,52,53]. Zargar et al. [54] indicated that an association between employees and managers, even if present, is unlikely to be effective if trust is lacking in that relationship. The presence of trust in a leader signifies the effectiveness of the manager and underscores their positive qualities and attributes. Furthermore, it was highlighted that the existence of trust within this relationship functions as the binding agent that fosters cohesion between employees and managers, thereby fostering the potential for organizational success.

2.4. Mediating Role of Trust in Leaders

Victor and Cullen [55] defined ‘trust in leader’ as a psychological state in which one party holds positive expectations towards another party, leading to a sense of comfort in displaying vulnerability and interpreting actions and intentions in a positive manner. Research has emphasized the pivotal role of leaders in generating positive outcomes for both employees and the organization [56], including job satisfaction, while also serving as a protective barrier against negative workplace experiences, such as bullying, burnout, or work–life imbalance ^{[54][55][57][58]}[54,55,57,58]. As previously mentioned, establishing a relationship of trust between employees and their leaders is a crucial factor for organizations when implementing sustainable HRM practices across different contexts. Consequently, the presence of such a relationship between employees and leaders contributes to the organization’s long-term benefits, encompassing progress, success, and numerous advantageous psychological outcomes. Kahn [59] contended that three factors can shape an employee’s engagement in their job performance across various dimensions, including physical, mental, and emotional levels. He posited that the key determinants governing employee engagement are psychological availability, psychological meaningfulness, and psychological safety. The concept of psychological safety is intricately linked with trust in leaders as an employee’s perception of feeling safe within the organization often corresponds with having trust in their leader [60]. Employees might be hesitant to openly share their thoughts and innovative ideas or actively engage with the organization if they are uncertain about the potential negative consequences of expressing their viewpoints ^{[4][61][62][63][64][65][66]}[4,61,62,63,64,65,66]. These factors serve as the underlying drivers determining whether employees will be motivated to perform their jobs effectively or not. Consequently, a robust sense of trust in leaders not only fosters feelings of appreciation, safety, and courage among employees but also cultivates a motivated and energized workforce, ultimately translating into enhanced job performance over the long term ^[67][68][67,68].