Here, we consider (a) definitions of policies, mechanisms involved, and the wide range of sectors that must be engaged for increasing physical activity (PA) at the population level, (b) a framework for the Comprehensive Analysis of Policy on Physical Activity, (c) the rationale for government involvement in PA and the policy roles that are unique to government, (d) criteria for effectiveness of the government role in PA policy, (e) the flexibility and adaptation needed for the government policy role in low- and middle-income countries (LMICs), (f) snapshots of PA policy in LMICs, and (g) a PA policy toolbox for LMICs (useful resources for policy planning). The World Health Organization and other agencies offer guidance on the areas for intervention. The World Health Organization’s Global Action Plan on Physical Activity 2018–2030 described active societies, environments, and peoples, and the International Society for Physical Activity and Health’s eight best investments covered settings such as schools, sport, workplaces, health care, urban design, and transport. Optimal investment occurs within and beyond the health sector, takes an upstream approach to primary prevention, and works to co-design strategies with all feasible and engaged agencies and sectors. LMIC governments must adapt this evidence to develop actions that are feasible within countries, building sequenced and logical national PA plans.