We present two studies that replicate and extend predictions made by implicit trait policy theory about the association between basic traits, knowledge, and behavior. Study 1 examined relations between personality traits, prosocial knowledge, and performance in a role-play casting participants (N = 102) as a physician dealing with challenging interpersonal situations. Study 2 (N = 197) replicated and extended these findings to include emotional intelligence (EI). In both studies, participants with higher prosocial knowledge scores behaved more prosocially. Mediation analyses suggest the relationship between individual differences, such as agreeableness and EI, and prosocial behavior is mediated by prosocial knowledge. Findings suggest basic traits influence prosocial behavior indirectly, through the acquisition of knowledge about how to behave in interpersonally challenging situations.