How Machiavellian leadership affects employees' happiness at work: the role of psychological contract breach and coworker exchange

In the hospitality industry, where service quality heavily depends on frontline employees' emotional engagement and wellbeing, leadership behaviors play a critical role in shaping employees' workplace experiences. Despite the growing attention to dark leadership styles, limited research has examined how Machiavellian leadership (ML) affects employees' happiness at work (HAW) and the underlying psychological mechanisms in hospitality settings. Drawing on social exchange theory, this study investigates the impact of ML on employees' HAW, the mediating role of psychological contract breach (PCB), and the moderating role of coworker exchange (CWX). Study 1 employed a scenario-based experiment, recruiting 188 employees from four five-star hotels in China to examine the causal relationship between ML and employees' HAW by manipulating ML conditions. Study 2 was conducted among frontline employees of 11 five-star hotels in Southwest China, utilizing a three-wave survey ( N = 483) to collect data. Structural equation modeling (SEM) was used to analyze the mediating role of PCB and the moderating effect of CWX in this relationship. The results indicate that ML significantly reduces employees' HAW. Furthermore, PCB mediates the negative impact of ML on employees' HAW, while CWX plays a significant moderating role in the relationship between ML and HAW. These findings extend the dark leadership literature by elucidating how ML disrupts social exchange processes and undermines employees' HAW in service-oriented organizations. From a practical perspective, the study highlights the importance of mitigating the negative consequences of ML through effective psychological contract management and by fostering high-quality CWX relationships in hospitality organizations.