How does the relationship between founding team composition and venture performance depend on the venture's strategy and business environment? Using data from a novel survey of 2,067 firms, we show that while diverse founding teams tend to exhibit higher performance, this is not universally true. We find that founding teams that are diverse are likely to achieve high performance in a competitive commercialization environment. On the other hand, technically focused founding teams are aligned with a cooperative commercialization environment and when the enterprise pursues an innovation strategy. These results are robust to corrections for endogenous team formation concerns. The findings suggest that ventures cannot ignore founding team composition and expect to later professionalize their top management teams to align with their strategy and environment.