This literature review examines the long-term retention of scholastic coaches and its impact on academic achievement and athletic success in secondary education settings. Although athletic participation is consistently associated with improved engagement and school connectedness, limited research isolates coaching tenure as a structural variable influencing dual-domain outcomes. This review synthesizes interdisciplinary scholarship from educational leadership, sport psychology, youth development, and organizational theory to analyze how sustained coaching stability influences grade point average, graduation rates, standardized test performance, athlete retention, team performance, and psychosocial development. Independent variables include coaching tenure, leadership style, and institutional support structures. Dependent variables include academic performance indicators and athletic success metrics. Grounded in self-determination theory, social learning theory, and transformational leadership theory, this review argues that long-term coaching retention enhances relational trust, motivational climate consistency, developmental alignment, and institutional coherence. Moderating variables such as socioeconomic context, administrative investment, burnout, and resource allocation are examined. Implications for educational policy, licensure preparation, and district-level leadership are discussed, and recommendations for longitudinal research exploring causal pathways are provided.