Field and purpose: Perhaps the importance of the coach's role in the sports environment, training sessions, sports camps, competitions, and eventually the adolescents' sports era does not need to be proven and explained much. Everyone who has a sports background has a variety of memories of the coaches' character, habits, behavior, mood, and remember their profound and lasting impact on themselves and other athletes. So to pay attention to the role of a successful coach by emphasizing the theory of positive youth development in sports does matter. Methodology: This research used the qualitative method, based on the grounded theory (Strauss-Corbin) approach. After library studies (including articles, books and, films), 13 in-depth and semi-structured interviews by experts were conducted. The selection method for interviewees was purposeful and by the snowball method. The selection criteria was the coaching philosophy based on helping adolescents flourish and develop their characters. Findings: These axial and selective codes were found and approved by Experts: Growth and development assets (individual and ecological assets, moral achievements, optimal development, psychological characteristics); Life skills (intrapersonal skills, interpersonal skills); Five Cs ( competence, confidence, connection, character, and caring); and Social achievements (appropriate social status, positive collective traits, professional lifestyle, reduction of high-risk behaviors, long-term benefits of sport). Conclusion: Paying attention to the benefits of sport and leisure, such as physical and mental health, relaxation, and getting ready for the next work week, is valuable, however it is necessary to concentrate sport's capacity for character development for future successes. Preparing the healthy and safe context for sports activities, applying the theory of positive youth development in sport, and the critical role of the coach, parents, and peers triangle are the main factors to access
