While the broad themes of population health go back centuries, its current rebirth, at least in the United States and Canada, began with the 1994 publication of Why Are Some People Healthy and Others Not? The Determinants of Health of Populations. 1 Although it offers no concise definition of population health, its authors said the concept's "linking thread [was] the common focus on trying to understand the determinants of health of populations." 1 In 2003, the most widely used current definition was published, stating that population health is "the health outcomes of a group of individuals, including the distribution of such outcomes within the group." 2 Kindig and Stoddart 2 believed the original concept, limited to the study of multiple determinants, to be too academic and not a health outcome and equity definition capable of stimulating strong population health policy. The strongest contemporary influence on growing the field of population health was the 2003 to 2016 Robert Wood Johnson Foundation Health and Society Scholars postdoctoral program. Of the 6 initial sites, only 3 were based in medical schools. Given the recognized critical role of the social determinants of health and, therefore, broader academic disciplines, such as sociology, economics, and public health, a hallmark of the Health and Society Scholars program was the development of strong multidisciplinary linkages across schools. It was explicitly recognized that, if population health outcomes derive from a multideterminant production function, multiple disciplines and policy sectors are required for understanding and action.