This paper studies the influence of CEO overconfidence on firms’ financial performance and corporate social responsibility (CSR) in the US real estate investment trust (REIT) market. CEO overconfidence has been shown to have both negative and positive influences on firms. This paper is the first to combine the two sides in a single framework. We find that firms with overconfident CEOs tend to have better CSR performance. In addition, better CSR performance can increase firms’ financial performance, but this positive relationship is undermined by the existence of overconfident CEOs. Our results not only shed light on the two sides of CEO overconfidence in the real estate sector, but also provide a new prospective for research on the CSR–financial performance relationship.