Adolescence is a critical transition period that sets the stage for adulthood and future health outcomes. Marked by key developmental milestones in brain maturation, increasing independence from parents, and greater connections to peers, adolescence is also a time of heightened risk for behavioral health problems, including substance use, violence, delinquency, and mental health issues. High school completion is a significant life course event and a powerful social determinant of health and health disparities. Jessor's Theory of Problem Behavior suggests that adolescent health behaviors and mental health problems are closely tied to poor educational outcomes and peer network formation in a reinforcing feedback loop, or vicious cycle, often leading to school failure, school disengagement, and drop-out. Schools are a novel platform through which vicious cycles can be disrupted and replaced with virtuous ones, simultaneously improving education and health. This article describes the potential for schools to transform health trajectories through interventions creating positive and supportive school climates. In addition, new models such as the Whole School Whole Community Whole Child Model promote whole child well-being, including cognitive, social, emotional, psychological, and physical development. Full-service community schools can serve as a hub coordinating and integrating all available resources to better respond to the needs of children and families. Present in every neighborhood, schools are a way to reach every school-age child and improve their health trajectories, providing an important platform for life course intervention research.