This study is a response to the call to examine motivational mechanisms linking proactive personality and outcomes. We examined proactive personality as a dispositional antecedent of work and life satisfaction, asserting that work engagement mediates the proactive personality—satisfaction relationships. With data collected from 365 employees from diverse backgrounds, we found support for our research model. Results of structural equation modeling indicate that proactive personality serves as a dispositional antecedent of work engagement, and work engagement fully mediated proactive personality’s relationship with job satisfaction and partially mediated its relationship with career satisfaction and life satisfaction. We discuss implications of results for theory and practice and offer suggestions for future research.