ABSTRACT This paper studies the short-lived reform experiment on grassroot democracy by the District Councils of Hong Kong in 2020–2021, following the landslide victory of candidates who supported the 2019 Anti-Extradition Movement of Hong Kong. It argues that the institutional positions and resources of local elections can serve as movement resources to support social and political movements, promote civic participation and community-building, and strengthen civil society. By a study of meeting documents and in-depth interviews with 50 pro-movement councillors, this paper recounted how movement activists made use of the local councils to support the movement, change funding allocation to counter clientelism, encourage grassroot participation and network with civil society. The window of political opportunity was quickly shut down with the imposition of the National Security Law for Hong Kong, but it showed the possibility of using local councils to further movement causes and grassroot democracy in a much-constrained non-democratic institutional setting.