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.'