Across multiple studies, we examine how identity conflict and enhancement within people affect performance in tasks that involve interactions between people through two mechanisms: role-immersion, operationalized as intrinsic motivation and role-taking, operationalized as perspective-taking. In Study 1, a longitudinal field study of customer service representatives (n=763) who simultaneously identify with multiple brands they represent to customers, we examine the relationships among identity conflict and enhancement, on the one hand, and objective sales performance, on the other. We find independent effects for identity conflict and enhancement on intrinsic motivation, perspective-taking and performance, such that identity conflict negatively and enhancement positively affects all three variables above and beyond average identification. Intrinsic motivation further mediates the relationships between identity conflict and enhancement on sales in a direction consistent with our theorizing. However, while significant, perspective-taking does not mediate these relationships in the expected direction, because it has a negative effect on sales. In Studies 2a and 2b, both experimental studies, we strengthen causal inference using an experimental moderation-of-process approach (Spencer, Zanna, & Fong, 2005) to constructively replicate and extend our findings. The paper demonstrates how multiple identities within people can have consequences for performance in tasks that involve interactions between people.