Our study is the first to provide systematic evidence of a hump-shaped CEO tenure-firm value relation. Cross-sectionally, firm value starts to decline after fewer years of CEO tenure in more dynamic industries, if CEOs are less adaptable to changes, and in the presence of greater labor market frictions. Overall, the dynamics of CEO-firm match quality appear to be a first-order driver of the CEO tenure-firm value association, as explained by CEO characteristics (adaptability), firm/industry characteristics (dynamism), and labor market characteristics that facilitate optimal matching between firms and CEOs.