Drawing on motivating language theory (MLT), this paper aims to demonstrate the effects of strategic leader speech in the context of internal corporate social responsibility (CSR) commu-nication. Specifically, the study (1) examines how leader motivating language strategies used in CSR communication influence employees’ CSR engagement and employee–organization relationships (EORs) and (2) identifies the mediator explaining the underlying psychological mechanism of the effects. Structural equation modeling was performed on a sample of 406 participants who are full-time and part-time employees in the U.S. The results showed that leader motivating language was positively associated with employees’ CSR engagement and EOR quality. Such relationships were significantly mediated by person–organization (PO) fit. This study advances CSR research and practice by explicating the impact of leaders’ oral communication in constructing employees’ CSR experiences and relationships with the employer.