As a voluntary behavior, employees’ advocacy can enhance organizations’ competitive advantage and reputation. Drawing on social identity theory, this study explores the mechanism of by which corporate social responsibility (CSR) perceptions influence employee advocacy behavior using a sample of 333 two-stage data. The results show that internal and external CSR perceptions have positive effects on employee advocacy behavior, organizational pride mediating the relationships between internal and external CSR perceptions and employee advocacy behavior. Responsible leadership strengthens the effects of internal and external CSR perceptions on organizational pride, as well as the indirect effects of organizational pride on the relationships between internal and external CSR perceptions and advocacy behavior. This study investigates how micro CSR affects advocacy behavior by introducing organizational pride and responsible leadership, thus advancing the micro CSR literature and providing directions for micro-level CSR research. The findings of this research provide guidance to managers by focusing on employee perceptions of CSR activities and organizational pride and by cultivating responsible leadership.