This longitudinal study examined how participation in organized activities during adolescence (ages 14–17) is associated with adjustment in emerging adulthood (age 21). It investigated the contribution of three dimensions of participation: activity portfolios (i.e., specific combinations of activity types), intensity, and duration. The sample included 287 Canadian adolescents. First, distinct activity portfolios were identified using a person-centered approach. Second, differences between portfolios were examined with regard to salient indicators of adjustment in emerging adulthood: depressive symptoms, problematic alcohol use, educational status, and civic engagement. Third, the contributions of participation intensity and duration were examined. Results revealed that certain portfolios were related in distinct ways to specific outcomes and that these differences depended on intensity or duration of participation.