Japan, which has the longest lived population in the world is taking public health seriously as a key objective of central and local governments. Relative to most OECD countries levels of risky health behaviour are low, but like Japan’s OECD peers a growing burden of non-communicable diseases, and a growing elderly population, are significant health challenges. This chapter, which appraises the overall architecture Japan’s public health system, points to areas of strength and weakness. In particular, this chapter stresses that in a highly decentralised system, where local government has significant responsibility for delivery of public health actions, Japan must establish a careful combination of strong central strategic leadership, local autonomy and responsiveness to local needs, and sharing of best practice across regions, and across sectors.