Based on the social learning theory and social exchange theory, this study explored the role-model sources of employees’ organizational citizenship behavior (OCB), including top management, supervisor, and firm executing corporate social responsibility (CSR) activities and investigated the effects of ethical leadership on the perceived CSR and OCB of employees from the perspective of the trickle-down model. Participants of the study included supervisors and their employees since the research involved different hierarchical levels of the company. The questionnaire was issued only to 30 listed and over-the-counter companies, based on the assumption that small companies cannot afford CSR campaigns. Finally, 112 supervisors and their 430 subordinates completed the survey. The study examined three ranking levels of top managers, supervisors and their employees; therefore, the analysis method was a three-level hierarchical linear model. The results revealed that the employees perceived CSR positively affects their OCB. Regarding the direct effect of cross levels, the ethical leadership of a top manager is positively associated with the ethical leadership of a supervisor. The ethical leadership of both a top manager and supervisor positively influences the OCB of employees; however, only that of a top manager positively affects the CSR perceived by employees. Regarding the trickle-down model of ethical leadership, the ethical leadership of a top manager positively influences employee OCB through the ethical leadership of a supervisor, which plays a partially mediating role. Moreover, the ethical leadership of a top manager positively affects employee OCB through their perceived CSR, which also plays a partially mediating role. The results suggested that corporations should understand how to exploit ethical leadership and the employee perceived CSR to enhance their OCB.