This study investigates how demographic board diversity and ownership structure shape Turkish firms' sustainable corporate performance (SCP) between 2013 and 2019. We use a panel dataset of 67 Borsa Istanbul (BIST) 100 indexed non‐financial and non‐utility firms. Based on logit and probit regression estimations, our empirical findings confirm that board diversity factors, including gender, nationality, experience, educational level, and tenure, are statistically significant and positively related to SCP. Contrary to expectations, ownership concentration has a significantly positive association with SCP. This study contributes insights about Turkish firms' board diversity that have practical implications for companies, regulators, and policymakers.