An open opponent of even a constitutional monarchy and of the Roman Catholic religion, Momoro keenly threw himself into the revolutionary cause and put his abilities at the service of the new ideas.

In the wake of this affair, which led to his imprisonment until September 1791, Momoro resumed his printing activities under his self-given title of "first printer of the national liberty", publishing Jacques-René Hébert's radical newspaper, Le Père Duchesne.

[citation needed] He was sent into the Vendée in May 1793, where he acted as deputy to Charles-Philippe Ronsin at the siege of the état-major at Saumur, in a mission to ensure the army fighting against the revolt there was well supplied.

Pushed onwards by a report by Saint-Just to the Convention denouncing the "complot de l'étranger" woven by the Indulgents and Exagérés, the committee decided on the arrest of the Hébertistes on 13 March 1794.

He was guillotined with Hébert, Ronsin, Vincent and other leading Hébertistes (Cloots, Jean Conrad de Kock) the following afternoon, 4 Germinal, Year II (24 March 1794).