At the time of the outbreak of the revolution (1789), Guadet was a leading lawyer in Bordeaux. In 1790 he became administrator of the Gironde département, and in 1791 he was made president of the département’s criminal tribunal. Later that year he was elected to the Revolutionary Legislative Assembly, which convened at Paris on October 1, by which time the revolution had already abolished France’s feudal institutions and restricted the authority of King Louis XVI. Guadet bitterly attacked the ministers of the king and was important in forcing the latter to appoint a predominantly Girondin ministry in March 1792.
After Louis dismissed the Girondin ministry in June, Guadet attempted, without success, to come to terms with the king. Although he opposed the popular insurrection that overthrew the monarchy on Aug. 10, 1792, he was elected a deputy to the National Convention, which succeeded the Legislative Assembly in September. At the trial of the king he voted for the death sentence, but with a respite pending appeal. Guadet vigorously opposed the radical democrats of the Jacobin Club and was one of the deputies expelled from the Convention in the Jacobin coup d’état of June 2, 1793. He fled from Paris to escape arrest but was captured at Saint-Émilion and guillotined.