We investigate earnings management by new powerful CEOs across firms’ ownership structure. Powerful CEOs are defined as those holding concomitantly the positions of CEO and Chairperson of the board. The results of our difference-in-differences analyses show that the arrival of new powerful CEOs leads to more earnings management in family firms without a majority blockholder. No significant result is found for firms with dispersed ownership and for family firms with a majority blockholder. This finding supports the idea of less effective CEO monitoring in family firms without a majority blockholder. Furthermore, we document that earnings are managed upward in these firms, and inflating earnings ultimately increases accounting performance. Overall, our results suggest that new CEOs’ influence on earnings management depends simultaneously on their power and on firms’ ownership structure.