How do different sources of social influence impact the likelihood of entrepreneurship? Using a longitudinal field experiment with a pre-test/post-test design, random assignment to an entrepreneur mentor of a student increases the likelihood of entrepreneurial careers, particularly for students whose parents were not entrepreneurs. Additional analysis shows the mentor influences the decision to join an early-stage venture, but not to become a founder. Performance data suggests that entrepreneurial influence is not encouraging “worse” entrepreneurship and may have helped students in joining or founding better-performing ventures. This contributes to the literature on social influence in entrepreneurship by examining the interaction between multiple sources of social influence and by using a randomized field experiment to overcome the endogenous process of tie formation.