Using six studies based on 23,823 individuals in diverse settings, we developed and validated a personality measure of Work Drive—a disposition to work long hours and extend oneself for one's job. The factor structure was confirmed in four settings. Work Drive was related to job performance showing incremental validity beyond cognitive aptitude and Big Five personality traits in five validation studies. It predicted academic performance at six different grade levels, even beyond Big Five traits. Construct validity was examined via work values, job involvement, normal personality scales, satisfaction measures, and cognitive ability. Little adverse impact was found. Occupational groups differed on Work Drive. Overall validity and areas of application were discussed.