The present research used data from Grades 8, 9, and 10 of the 4-H Study of Positive Youth Development, a longitudinal study involving U.S. adolescents, in order to better elucidate the process through which the strengths of youth and the ecological resources promoting healthy development (such as out-of-school-time programs) may contribute to thriving. We examined the relationship between adolescents' self-regulation skills (selection, optimization, and compensation) and their participation in youth development (YD) programs across Grades 8 and 9 in predicting Grade 10 PYD and Contribution. Results indicated that while self-regulation skills alone predicted PYD, self regulation and YD program participation both predicted Contribution. In addition, Grade 8 YD participation positively predicted Grade 9 self regulation, which, in turn, predicted Grade 10 PYD and Contribution. We discuss how the alignment of youth strengths and resources within the environment may promote positive youth development. (Contains 1 figure and 3 tables.)