This study investigates the effects of geographical regions and related-party transactions on corporate social responsibility (CSR) and long-term mergers and acquisitions (M&A) performance linkage. We conduct a Heckman two-stage model analysis, using data from listed firms in the Shanghai and Shenzhen stock exchange markets in China. The results indicate that: (1) buyers’ CSR performance has a significant and positive effect on long-term M&A performance. (2) Significant differences exist across geographical regions in the links between CSR and long-term M&A performance. In our study, the effects of CSR on long-term M&A performance were positive and significant in a sub-sample of firms located in the eastern region, but the effects were negative and insignificant in a sub-sample of firms located in regions other than in the east. (3) Related-party M&A transactions experience more positive and significant CSR long-term M&A performance linkage, compared to non-related party M&A transactions. Our findings might provide more robust evidence to CSR performance linkage, as we have examined the linkage in a special context of M&A activities, using a Heckman two-stage model to alleviate endogeneity bias. We also bring further insights into the effects of two contingent factors (geographical regions and related-party transactions) on the CSR-performance linkage. The findings of this article suggest that it is reasonable for firms to act socially responsibly when generating economic benefits. Policy makers should consider how to encourage firms to better fulfill CSR through improving the market environment and by enhancing their levels of supervision.