This chapter puts children and childhoods at the forefront of critical social work by drawing on the theoretical legacy of Michel Foucault and the concept of biopolitics. While children and childhoods were not the primary focus of his work, it is argued that Foucault made significant contributions to our understanding of child welfare social work as a biopolitical discipline and practice, as well as contemporary rights discourses. The chapter examines how biopolitics reduces ‘the social’, particularly the social worlds of children, to affective ‘milieus’, stages, lives that can be intervened in from within and invested in for the future. The notion of biowelfare is used to discuss recent biopolitical articulations which focus on the malleable resilient subject as an end-goal in anticipation of a neoliberal uncertain future. The chapter proposes critical childhood studies as a useful lens for navigating a terrain in which objectification and reduction of childhoods concurrently inform rights and justice discourses, making debate and contestation challenging.