Although proactive personality (Bateman & Crant, 1993), as a relatively stable disposition to bring about change in one's environment, is a central construct in the management and organizational behavior literature, questions have arisen about its definition and structure. To answer these questions, we present a tripartite model of proactive personality consisting of 3 dimensions: perception (i.e., perceiving opportunities for change), implementation (i.e., planning and executing change), and perseverance (i.e., persisting until the change is realized). Exploratory factor analysis informed the construction of a 14-item scale, and confirmatory factor analyses supported the validity of the scale. The new scale demonstrated satisfactory reliability and accounted for significant variance in task performance above that of original proactive personality, personal initiative, conscientiousness, and social desirability. Tripartite proactive personality might provide a more nuanced view of dispositional proactivity and greater predictive power than the original unidimensional proactive personality.