Notwithstanding the claims to equality associated with (neo)liberal democratic citizenship, capitalist cities are characterized by stark inequalities in access to land and living space. In response, grassroots movements and marginalized residents are struggling for a more socially and ecologically just urbanism. We conceptualize these movements as democratizing cities by practicing urban citizenship, following the tradition of scholarship that loosens citizenship from its confines as a bundle of rights and responsibilities conferred by nation-states on individuals. Such practices seek to realize existing rights rarely extended to marginalized urban residents and advocate for novel rights, e.g. to shelter, place, the city, and a voice in governance decisions affecting residents’ lives. We analyze the strategies and tactics pursued by Jakarta’s housing justice movement from Indonesia's democratization (reformasi) in 1998 to the present, seeking to assert and expand urban citizenship rights. Creatively moving between existing invited political spaces of citizenship and newly invented spaces, depending on political opportunity structures, movement leadership styles and local circumstances, the movement has experimented with strategies and tactics ranging from confrontation to negotiation, signing political contracts with governors, to now seeking to participate in the formal political process. We critically reflect especially on using a political contract to facilitate rights to place and security of tenure in ‘illegal’ kampungs. We conclude by reflecting on the insights our case study brings to how urban poor social movements’ citizenship practices contribute to democratizing cities and advancing socio-spatial justice.