In this study, we examine the effects of proactive personality on employees’ perceptions of conflict in the work and family domains and work-related outcomes. We test our hypotheses using survey data collected from 1,150 employees. Our results indicate that proactive personality is associated with increased work-interference-in-family (WIF) but decreased family-interference-in-work (FIW). These opposing, domain-specific effects have masked hitherto hidden relationships that we highlight in this study. Using structural equation modeling, we demonstrate that WIF and FIW function as simultaneous mediating variables between proactive personality and turnover intentions as well as between proactive personality and job performance. Through an investigation of underlying mechanisms, this study advances a more nuanced portrait of how individual differences shape individual and organizational outcomes.