Recent years have seen migration rise to the top of political agendas around the world. In December 2018 states adopted two Global Compacts, one on migration and one on refugees, establishing roadmaps for the future of international cooperation relevant to population movements. While often attributed to the “migration crises” of 2015, the Global Compacts are also the product of more than one hundred years of institution-building during which the world has evolved tremendously. Building on theoretical insights from the Advocacy Coalition Framework (ACF), and the methodological principles of process-tracing, the dissertation tells the story of how migration has evolved as a global policy issue since 1919. Framing analysis is used to analyse the different ways that migration has been framed, by whom, and to what end in order to draw attention to the role of power in the evolution of global migration governance. Drawing on interviews with 43 key protagonists, actors involved in global-level discussions on migration, and the UN archives, the dissertation investigates how migration became a global governance issue, and the role played by the UN in this process.