She was born Anne-Josèphe Terwagne, in Méricourt. An unsuccessful opera singer, she joined the revolutionary movement shortly after the storming of the Bastille. She was involved with the Women's March, and was in the crowd when the King was forced to pin a revolutionary cockade on his hat.
Méricourt cut a unique figure in a crowd, with her preferred outfit featuring a riding habit, man's hat, and pistols. In the early days of the revolution, she regularly attended the National Assembly, watching from the galleries, and following it when it moved from Versailles to Paris.
Méricourt left Paris in 1790, and was arrested by the Austrians, who would later release her. She returned to Paris in 1792, eagerly re-joining the revolutionary cause. Her imprisonment increased her notoriety and she was invited to speak at the Jacobin club.