Professional baseball leagues in North America and Japan have similar institutions governing their sport. All Major League Baseball (MLB) teams and Nippon Professional Baseball (NPB) teams are governed by associations of team owners who make major decisions and hire a commissioner to enforce rules, manage league operations, and preserve the integrity of baseball. We present narrative histories of the role of the commissioner in MLB and NPB and conclude that MLB owners have typically delegated more authority to the commissioner than NPB owners. We find that NPB and MLB commissioners differ with respect to their age at hire, length of the contract term, and their tenure on the job. Our tentative explanation rests on cross-country differences in the extent of scandals affecting the integrity of the game, the relative power of teams with large fan bases in league decision making, and the stronger position of NPB teams vis-à-vis their players.