This research aimed to examine (1) the effect of domain overlap between CSR activity and Corporate Social Irresponsibility (CSI) (i.e., CSR strongly or weakly associated with CSI) on attitude toward the sponsor via CSR perception of sponsor and (2) the moderating effects of perceived firm-serving motive for CSR activity. The authors conducted two experiment studies: Study 1 tested the mediation model; Study 2 assessed the moderated mediation model. Participants reported a less positive attitude toward the sponsor when CSR was strongly associated with CSI (i.e., in the high CSR-CSI domain overlap) than when CSR was weakly associated with CSI (i.e., in the low CSR-CSI domain overlap). CSR perception of sponsor mediated the relationship between the CSR-CSI domain overlap and attitude toward the sponsor. The positive effect of the low CSR-CSI domain overlap was weakened when participants attributed firm-serving motives to the sponsor. The findings provided scientific contributions to sponsors with CSI.