Abstract In a normative sample of 205 children ages 8–12, tracked into adulthood, we examined the predictive links between four childhood personality traits—Mastery Motivation, Academic Conscientiousness, Surgency, and Agreeableness—and adult personality and adaptation 20 years later. Personality demonstrated modest to moderate continuity over those two decades and showed significant predictive validity for success in adult life, including academic attainment, work competence, rule-abiding versus antisocial conduct, and romantic and friend relationships. Results indicated that personality shows coherent patterns over time in terms of both stability and linkages to adaptive behavior. Explicating the processes underlying such patterns is the next frontier for a truly developmental science of personality.