The rising star hypothesis proposes that characteristics of "rising star" protégés already set them up for success, such that mentoring is a byproduct of their ambition. Alternatively, the influential mentor hypothesis states that protégés experience success due to the positive influence of mentoring. Herein, we test whether rising star characteristics (need for achievement and career initiative behaviors) precede or follow informal mentorship. Using data from a sample of 94 protégés (recruited from a hospital) over two time points (six-week lag), we found best evidence for a mix of the rising star and influential mentor hypotheses, in which career initiative behaviors predict the number of informal mentors, and in turn, need for achievement. Cross-lagged effects were probed and provide evidence that the benefits of informal mentoring does not seem to extend to formal mentoring. Practical implications are highlighted, including the benefits of multiple mentors and alternatives to traditional mentoring.