Over the last fifteen to twenty years, the idea of the ‘rise of cities’ as global political actors has gained prominence in international policy circles. The narrative takes credence from growing scepticism regarding the ability of sovereign states to tackle contemporary global issues, from climate change to migration. This dissertation scrutinises the rise of cities from a political theory perspective, by taking it as indicative of an effort to recover political agency beyond state sovereignty. Chapter 1 elucidates the rise of cities as a discourse claiming political legitimacy by heralding cities as efficient governing agents. In the context of the global age, marked by the globalisation of infrastructure and the extension of relevant political communities, cities are seen as more capable than states to secure liveability despite, and against, impending global threats. Drawing on ethnographic engagement with cities, international organisations, and transnational city networks, I then critically investigate the forms of agency effectively developed through the rise of cities both in global governance (chapter 2) and in cities themselves (chapter 3). While the concern with efficacy drives the co-optation of cities by international organisations like the United Nations, within cities internationalisation is pursued as a means to secure liveability for a changing community at the local level. In both cases, the rise of cities as global actors reveals the flaws of sovereign agency, but still remains constrained by the sovereignty framework. In chapter 4, I offer an alternative conceptualisation of political agency by foregrounding the city as a material site of liveability. I argue that because cities are both nodes of global infrastructure and sites of human plurality, city-making requires a form of open-ended agency which is better suited than sovereignty to the demands of the global age — making participation in city-making a key political issue. Throughout the dissertation, I also consider how the governance of cities can contribute to the project of building a liveable world for all in the context of an extending global political community.