This article interrupts the linear narrative that posits the conferment of citizenship (legal naturalisation) as the ‘natural’ outcome of citizenisation. Where the scholarship on citizenship and migration privileges the institutional life of citizenisation – where naturalisation appears as a discrete event at the end of the ‘citizenisation’ continuum – the social life of citizenisation includes naturalisation as an ontological process but is not reducible to it. ‘Ontological process’ refers to the ways in which different categories or locales of existence (the self, society, culture, the state, the nation, histories, geographies) are combined to produce understandings of what citizenship ‘really is’. Drawing on critical policy studies, ‘the social life’ of citizenisation and naturalisation rejects a conception of policy as a coercive instrument of the state or as a fixed document. I then turn to feminist science and technology scholars Annemarie Mol’s (2002) ‘ontological politics’ and Charis Thompson’s (2005) ‘ontological choreographies’ as useful frameworks to work with for tracing ontological processes within practices of citizenisation and naturalisation. To illustrate, the article builds on the widely used opposition between ascribed (birthright) and chosen citizenship (naturalisation) to show how the distinction falls apart when we understand naturalisation as part of the normalisation of such assumptions and their effects on global inequalities. The analysis demonstrates how the proposed analytical framework puts into relief joint processes of ontologising, normalising, subjectification, and stratification. Understanding how citizenisation and naturalisation function in tandem institutionally and socially is important if we are to gain a fuller grasp of how old and new forms of inequalities are refigured in twenty-first century citizenship.