Although the composition of the board of directors has important implications for different aspects of firm performance, prior studies tend to focus on financial performance. The effects of board composition on corporate social responsibility (CSR) performance remain an under-researched area, particularly in the period following the enactment of the Sarbanes-Oxley Act of 2002 (SOX). This article specifically examines two important aspects of board composition (i.e., the presence of outside directors and the presence of women directors) and their relationship with CSR performance in the Post-SOX era. With data covering over 500 of the largest companies listed on the U.S. stock exchanges and spanning 64 different industries, we find empirical evidence showing that greater presence of outside and women directors is linked to better CSR performance within a firm's industry. Treating CSR performance as the reflection of a firm's moral legitimacy, our study suggests that deliberate structuring of corporate boards may be an effective approach to enhance a firm's moral legitimacy.