In recent years, researchers working on the nexus between migration and politics in countries of origin have started to pay more attention to the local level, but important empirical and theoretical gaps remain. By drawing upon semi-structured interviews, field observation and documentary research, this paper presents the exploratory case study of the 2012 local elections in Borșa, Romania, when an emigrant became mayor due to the mass mobilisation of the diaspora. Our analysis makes a three-fold contribution to the emerging literature on the impact of migration on local politics. First, it provides fresh empirical evidence from the largely underexplored context of intra-EU mobility. Second, it proposes an inductive classification of the factors and mechanisms at micro-, meso- and macro-level that allowed for the political change in Borșa in 2012, thus providing the basis for a framework of the prerequisites for migrant-led political change at the local level. This includes recognising ad hoc transnational mobility as a distinct mechanism of migrant political mobilisation. Third, by identifying also some of the post-election challenges faced by the migrant political actors, we extend Danielson’s (2017) framework of ‘acceptance’, ‘rejection’ and ‘integration' by proposing the category of ‘negotiated political integration’. [ABSTRACT FROM AUTHOR]