The purpose of this study was to examine the relationship between leader experience and team performance. Major League Baseball managers from 1903 to 2006 provided the context within which the relationships were studied. Experience was conceptualized in terms of games managed and seasons managed at the occupational and organizational levels. Cross-sectional analyses revealed a small but significant positive relationship between all types of experience and team performance after controlling for team ability. Analyzing the data longitudinally with random coefficient modeling, however, revealed only one significant experience-performance relationship. After controlling for team ability, there is evidence that managers improve team performance until a peak at about 1200 games. There is no evidence of a positive linear relationship of any kind or that this improvement transfers to other teams.