The relationship between hometown attachment (HA) and corporate social responsibility (CSR) is a topic to be explored in depth. We measured the HA by the Chinese diaspora background and the immigrant culture of the ultimate controllers of the firm and employed the sample of Chinese non-financial private-listed companies in Shanghai and Shenzhen from 2003 to 2019 to investigate the impact of the HA on overseas Chinese entrepreneurs on CSR. We found that the HA of the overseas Chinese ultimate controller significantly increases the level of CSR, and this promoting effect rises when the firm ultimately held by the overseas Chinese entrepreneur is registered in the expatriate hometown. Our further analysis found that the personal characteristics of overseas Chinese entrepreneurs and regional cultural differences have a moderating effect on the above relationship. In particular, we found that overseas Chinese entrepreneurs who are women or with lower academic qualifications have a stronger sense of CSR. Moreover, in areas with low marketization or a high level of social trust, HA of overseas Chinese entrepreneurs plays a more active role in CSR. The results remain robust after the robustness test and the endogenous test. The conclusion of this study not only highlights the impact of psychological factors on the level of CSR but also provides a reference for the study of the decision-making behavior of overseas Chinese entrepreneurs.