Schools are ideal settings to promote adolescent physical activity (PA), yet school-based interventions have shown limited long-term impact. This position paper presents key issues surrounding school-based PA interventions. Collaborative conceptual thinking drawing on multi-author expertise and available evidence advanced our understanding and opinion. Key arguments: 1) the adoption of a systems approach, which maximizes partnership action and leverages policy, is crucial for understanding the complexities of implementing whole-school programs; 2) a reorientation to an assets perspective optimizes existing strengths and resources allowing greater emphasis on the full range of physical, cognitive, emotional and social benefits that PA provides, and 3) a move beyond traditional positivist research designs to advance our knowledge of what works better, for whom and in what context is needed for greater progress We provide suggestions, specifically advocating for systems approaches, as a realistic way to improve how we support PA in schools in the future.