At the outbreak of the French Revolution in 1789, Lakanal was working as a teacher. In 1792 he was elected to the revolutionary legislature known as the National Convention. He voted for the execution of King Louis XVI (January 1793).
As a member of the Convention’s Committee of Public Instruction, Lakanal in June 1793 presented a bill (Projet d’éducation nationale) proposing that the state provide free elementary education for boys and girls. The plan was rejected, but, after the fall of Robespierre’s Jacobin regime (1794), Lakanal became president of the education committee. In October he presented a version of his plan for elementary schools that was enforced for about a year. He also presented a plan for écoles centrales (secondary schools), which was followed until the lycées were set up in 1802. In 1795 he started the école normale for training teachers. Proscribed as a regicide, he went to the United States in 1816 after the second Restoration of the monarchy. While he was a resident of Kentucky, he journeyed widely in the South, visiting states such as Louisiana and Alabama. He served as president of the College of New Orleans (1822–23). Lakanal returned to France in 1834.