Youth participation in community-based, structured out-of-school time programs (OST) has been found to promote positive developmental outcomes by providing youth with resources to build interpersonal relationships and essential life skills. The increasing prevalence and multiplicity of youth participation in these activities leads us to expand the research evidence regarding the relation between program participation and positive youth development, with a focus on identifying nuanced patterns of OST participation that consider the breadth and frequency of activities across different types of programs. We apply this pattern-centered approach to analyzing how and for whom these activities may promote youth academic competence and character. The study sample is a subset of 700 middle-school youth of diverse race and ethnicity who primarily reside in low-resource areas of South Carolina. Survey respondents indicated their involvement in specific OST activities as well as the frequency of participation. PYD outcomes were measured with items from the academic competence and character subscales of the PYD-Short form. We conducted a latent profile analysis (LPA) of the activity participation variables to determine OST profile membership based on youth self-reported participation in OST activities. A series of analyses following the LPA examined the links between OST participation profile membership and academic competence and character as well as potential variation by race and gender. Our findings of consistent positive main effects of OST participation profiles on these outcomes across demographic groups underscore the value of diverse OST program participation for enhancing well-being and healthy development in early adolescence.