We thank Glenn Carroll, Jeffrey Pfeffer, Bob Sutton, and James Wade for comments on earlier drafts of this paper. We measure the effects of motivation and ability on the early career success of a sample of Master's of Business Administration (MBA) graduates in the early years of their careers. We argue that performance is a joint effect of two important individual characteristics: general cognitive ability and motivation. General cognitive ability, which is representative of the general population, refers to individual differences in tasks or pursuits that demand mental effort, such as abstraction, rule inference, generalization, and manipulating or transforming problems. Motivation is conceptualized as a stable mental state that energizes human behavior. Results show that the combination of high general cognitive ability and motivation is significantly associated with more early career success. MBAs who were both smarter and worked harder were more successful in their job search upon graduation, were earning higher salaries, had more rapid pay increases, and received more promotions in their early careers. These findings add to the mounting evidence that studying enduring individual characteristics is critical to predicting behavior.' In the past several years, organizational researchers have engaged in a rather artificial debate about the extent to which individual differences or dispositions predict job outcomes such as attitudes and behaviors (e.g., Davis-Blake and Pfeffer, 1989). While the debate is provocative, a careful examination indicates that there may be less substance to this debate than it seems. By now, most organizational researchers acknowledge the fundamental importance of situational effects, the existence of stable individual differences, and their interaction as causes of behavior (Wright and Mischel, 1987; Chatman, 1989). The controversy lies in questions about the usefulness of measuring dispositions that are sometimes poorly specified and lack reliability and validity, the absence of well-developed theoretical justifications for constructs for given situations, and the frequent use of cross-sectional research designs that do not permit adequate longitudinal testing of clearly specified hypotheses (e.g., Weiss and Adler, 1984). It is clear that poorly designed studies of dispositions exist, but some stable individual differences may predict important attitudes and behavior. Intelligence, or general cognitive ability (GCA),-has a long, well-documented history of research that reliably predicts important organizational outcomes such as job performance and career success (e.g., House, Howard, and Walker, 1992). Hunter (1986: 340) reported a review of "hundreds of studies showing that general cognitive ability predicts job performance in all jobs." The predictive ability of GCA increases for jobs or situations that require increased information processing. This is consistent with Wright and Mischel's (1987) competency-demand hypothesis, which implies that people with more general cognitive abil...