The current literature expands the existing knowledge of the antecedents of proactive environmental strategies (PES) in family firms from the perspectives of institutional, market and family involvement logics. However, scholars have not considered the influence of key family decision-makers and their characteristics in this regard. Based on the ability and willingness framework, this study focuses on how founders' religiosity affects family firms' PES. Using data from the 2010 Chinese Private Enterprise Survey conducted by Chinese officials, we found that founders' religiosity (...) drives family firms to implement PES. Altruistic and long-term orientation are the internal mechanisms of this effect. Founders' political status enhances the positive impact of their religiosity on PES, whereas the founders' need for socioemotional wealth protection weakens the relationship between founders' religiosity and family firms' PES. We also found that Eastern and Western founders' religiosity has an asymmetric effect on family firms' PES. This study contributes to the literature on the PES of family firms, the family firm's ability and willingness framework, and family business heterogeneity. (shrink)