Being asked to give the Charles H. McCloy research lecture is one of the highlights of the author's academic career. Although McCloy's primary area of expertise was measurement and the analysis of motor skills, he also shared an avid interest in youth development through sport and physical activity. In this article, the author features youth sport as a unique social context with the potential for developing youth psychologically, socially, and physically and, thus, should not be excluded when talking about youth physical activity and associated health and skill benefits. She organizes this article into sections that integrate youth development research with McCloy's contributions to this area. First, she discusses the importance of adopting a developmental theoretical perspective to studying children's experiences in sport, a pervasive view throughout her research. With this worldview, she then reviews lines of research on positive youth development through sport--self-perceptions, motivation, character development, social relationships, and observational learning. Third, she shares an important developmental transition in her career that led to using mixed methodologies for understanding youth development. Fourth, she shares findings from the longitudinal research evaluating The First Tee, a youth development program using sport as a context to promote life skills and positive outcomes. She concludes that people can maximize the benefits of youth sport participation when they adopt an interdisciplinary perspective--integrating theory and research from developmental sport psychology, kinesiology, child and adolescent psychology, educational psychology, and public health, among other disciplines central to of this phenomenon.