Significance We followed a population-representative cohort of children from birth to their mid-forties. As adults, children with better self-control aged more slowly in their bodies; showed fewer signs of brain aging; and were more equipped to manage later-life health, financial, and social demands. The effects of children’s self-control were separable from their socioeconomic origins and intelligence. Children changed in their rank order of self-control across age, suggesting the hypothesis that it is a malleable intervention target. Adults’ self-control was associated with their aging outcomes independently of their childhood self-control, indicating that midlife might offer another intervention window. Programs that are successful in increasing self-control might extend both the length (life span) and quality (health span) of life.