The significant need to achieve business sustainability calls for a new business perspective grounded on leaders’ abilities and the effective execution of green human resource management (GHRM). This study aims to emphasize the role of ethical leadership and GHRM in moving organizations toward sustainability. GHRM supports companies to match their corporate strategies to the environment mainly in the presence of ethical leaders who can walk the talk and the provision of adequate practices and training by HRM to foster a working environment, where employees can exhibit creativity, passion, and positive behaviors towards sustainability. Specifically, this research studies the impact of ethical leaders via GHRM and harmonious environmental passion on employees’ green behaviors using a quantitative method in which a dyadic approach (supervisor–employee) was employed to collect data from two sources through a structured questionnaire from non-profit organizations in Lebanon. The research hypotheses were tested using Partial Least-Squares–Structural Equation Modeling (PLS-SEM). The results showed a significant impact of ethical leadership on employees’ green behaviors. In addition, GHRM and harmonious environmental passion mediated the relationship between ethical leadership and employees’ green behaviors. Besides, it was noticed that green creativity strengthened the association between ethical leadership and GHRM, while a psychological green climate strengthened the association between GHRM and employees’ green behaviors. The study has practical implications for leaders and policymakers who are apprehensive about business sustainability.