This study examines the influence of public environmental concern on corporate environmental responsibility (CER) in China, utilizing panel data spanning from 2012 to 2022. Employing a panel threshold model, we investigate the moderating role of equity concentration in this relationship. Our findings reveal a positive association between heightened public environmental concern and increased CER. However, this positive effect is attenuated when equity concentration surpasses a specific threshold, indicating a potential impediment to CER under concentrated ownership structures. Further analysis elucidates the underlying mechanism, demonstrating that public environmental concern enhances CER by fostering executive environmental awareness—an internal driving force. Additionally, we identify a negative moderating effect of environmental taxes and fees-an external factor-on the relationship between public environmental concern and CER. This study contributes to the existing literature by providing novel insights into CER drivers. It encompasses both internal organizational factors and external institutional pressures within China’s rapidly developing economy.