Childhood self-control has been linked with better health, criminal justice, and economic outcomes in adulthood in predominately white cohorts outside of the United States. We investigated whether self-control in first grade predicted success in the transition to adulthood in a longitudinal cohort of first graders who participated in a universal intervention trial to prevent poor achievement and reduce aggression in Baltimore schools. We also explored whether the intervention moderated the relationship between self-control and young adult outcomes. Teachers rated self-control using the Teacher Observation of Classroom Adaptation-Revised. Study outcomes were on-time high school graduation, college participation, teen pregnancy, substance use disorder, criminal justice system involvement, and incarceration (ages 19–26). Latent profile analysis was used to identify classes of childhood self-control. A high self-control class (n = 279, 48.1%), inattentive class (n = 201, 35.3%), and inattentive/hyperactive class (n = 90, 16.6%) were identified. Children with better self-control were more likely to graduate on time and attend college; no significant class differences were found for teen pregnancy, substance use disorder, criminal justice system involvement, or incarceration. A classroom-based intervention reduced criminal justice system involvement and substance use disorder among children with high self-control. Early interventions to promote child self-control may have long-term individual and social benefits.