Studying the transformation of France’s social security system between 1970 and 2020 reveals a recomposition of the power of unelected governmental elites. The institutionalization of a group of “welfare elites” characterized by a new sociological profile (social background and career paths) has led to a reshaping of policy governance (“Iron Triangle”). These High civil servants have carried out a program of “sustainable social welfare,” reinforcing state interventionism in health and social insurance policies. In the context of this program’s implementation, they have developed the role of custodians of state policies. This strengthening of the French state’s capacity sheds new light on the question of its reconfiguration.