Physical inactivity is one of the leading causes of death, disability, and health care costs, but resources and other investments in promoting physical activity are neither proportional to nor ideally suited to address the problem, especially in the United States. Capacity for physical activity promotion is lacking, when compared to the response to other major health risk and protective behaviors. The authors of the commentaries in this special issue were asked to identify key issues from a variety of perspectives and to recommend actions that can be taken now to increase physical activity across the population so that all segments of society benefit, especially those at high risk of chronic diseases. The goal is to stimulate research institutions, public health agencies at all levels, and policy makers to raise physical activity as a priority commensurate with other pressing public health concerns.