How does manager quality affect subordinates' career progression? We examine the causal effect of manager quality on workers' career outcomes in the context of managerial teams at a large construction firm. We exploit quasi-random variation in worker-manager matching through frequent project reassignments to identify the causal effect of high-quality managers on promotions. Working under a high-quality manager increases workers' subsequent promotion rates by 13 percentage points. We provide evidence in support of managerial human capital transmission as the primary mechanism: effects are concentrated among workers and positions that require most managerial skills and exposed workers earn significantly higher performance-based bonuses.