In this study, the impact of board nationality and educational diversity on corporate social responsibility is investigated, by applying a fixed-effect model, instrumental variable approach (IV-GMM), and dynamic panel model (GMM) estimator to account for endogeneity issues, on a sample of Australian listed firms over 10 years from 2010 to 2020. The study findings reveal a significant positive relationship between board nationality diversity and CSR performance and its-related subdimensions including environmental performance and social performance. Furthermore, we find that educational diversity is positively and significantly related to CSR performance and environmental performance, though not to social performance. The findings remained robust under the instrumental variable approach and dynamic panel model. Additional tests compare between two groups of firms—those from heavily and less regulated sectors—and find that the former group has more educated directors, but a similar level of nationality diversity is found among both sectors. Although diversity in terms of nationality and education is still modest at best, its effect on CSR performance and its related sub-dimensions is more pronounced within heavily regulated sectors only. This result contends that when board nationality diversity and educational diversity are properly incentivized (with regulating CSR activities, for instance), the board tends to improve the social and environmental activities of the firm.