This article deals with the impact of intra-party transformations and access to power on the visions of political participation of activists taking part in populist anti-establishment parties with a strong emphasis on digital participation, using the Five Star Movement (M5S) as a case study. Going beyond studies conceiving the M5S as a populist and digital party, we argue that activists support a democratic ideal based on a civic culture involving a demanding role for ordinary citizens, who should be highly interested in politics and involved locally on a day-today basis. A negative vision of the Italian citizen judged as incapable of playing this role accompanies this ideal. Our article also demonstrates how political involvement in the M5S transformed the visions of activists, making them warier of direct democracy and more disillusioned about their fellow citizens. The analysis relies on qualitative semi-directed interviews with former and current M5S activists with diversified socio-demographics, political and participation trajectories in two Italian regions. More broadly, our article shows that the effects of entering government and intra-party reforms reinforcing the leadership at the expense of local activists are particularly strong in anti-establishment parties and clash with the conceptions of participation supported by activists.