Physical activity is important for well‐being across the life span. However, links between patterns of adolescent activity, competence perceptions, and young adult outcomes are underexplored. We used data from seven waves of the 4‐H Study of Positive Youth Development (N = 5,961) to assess patterns of adolescent athletic participation, whether these patterns were associated with self‐perceived athletic competence and young adult physical activity, depressive symptoms, and health, and associations between changes in participation across adolescence and young adult outcomes. Competence perceptions were associated with increased participation, and more active adolescents had higher rates of adult athletic activity, with links to better health and fewer depressive symptoms. We discuss results in light of the importance of using person‐centered analyses to understand active lifestyles.