Physical activity-based positive youth development (PYD) programs can serve to empower and alleviate barriers to development for at-risk youth. Youth leaders may play an important role in these programs to foster the development of their younger peers, while mutually benefiting from the program as they foster and apply skills such as leadership, communication, and self-direction. This reciprocal relationship may also be moderated by perceptions of trust, relatability, familiarity, and needs support. Currently there is a gap in literature that has examined youth leadership in PA-based PYD. The purpose of this study is to explore perspectives and experiences of youth leadership in Start2Finish's Running and Reading Club, a PA-based PYD program targeted for at-risk youth. Semi-structured interviews were conducted with program participants (aged 9-12) and youth leaders (aged 13-17) from four clubs in Toronto, asking about their general experiences in the program, their interactions with each other and the adult leaders, and perceptions of their development. Results indicate that youth leaders perceive that their interactions with youth and adults have helped them develop greater confidence in themselves, attainment of life skills (e.g. leadership, communication, responsibility), and have helped participants develop new skills. Youth participants perceive that youth leaders help to facilitate a more engaging environment, however, they attribute their development more to engagement in the activities themselves and the support of their adult leaders. This research will contribute to current gaps in the literature on youth leaders within the context of PYD programs, as well as provide practical recommendations to improve PYD programming.