This paper uses a comparative case study of Canada and the USA to argue that, in order to fully understand the associations between population health and the socioeconomic environment we must begin to place importance on the dynamic aspect of these factors--examining them as they evolve over time. In particular, for institutional and policy shifts that often unfold over decades, population health must attend to these big, slow moving processes by adopting a historical perspective to the knowledge base. We compare Canada and the USA on basic health outcomes and a range of determinants of health for which routine data have been collected for all or most of the period between 1950 and the present. During the analysis that follows, we are able to establish that, at the level of society (i) greater economic well being and spending on health care does not yield better health outcomes, that (ii) public provision and income redistribution trump economic success where population health is concerned, and (iii) that the gradual development of public provision represents the buildup of social infrastructure that has long-lasting effects on health status. Our case study shows what can be gleaned from a comparative perspective and a long-term view. The long view allows us to detect the gradual divergence in health status between these two societies and to trace potential institutional causes that would otherwise go unnoticed. The perspective introduced here, and in particular the comparison of Canada and the USA, provides strong support for the use of cross-national comparative work, and a historical perspective on the investigation of societies that successfully support population health.