Born in Paris, the son of a pastry-cook, he was educated at the Lycée Louis-le-Grand, and after his father's death he carried on the business for a time.
After the production of his first vaudeville, Les Deux Jumelles (1734), circumstances enabled him to relinquish business and devote himself entirely to the drama.
He provided many pieces anonymously for the lesser theatres, and first put his name to La Chercheuse d'esprit, which was produced in 1741.
Favart became director of the Opéra-Comique, and in 1745 married Marie Justine Benoîte Duronceray, a beautiful young dancer, singer and actress, who as "Mlle Chantilly" had made a successful début the year before.
By their united talents and labours, the Opéra-Comique rose to such a height of success that it aroused the jealousy of the rival Comédie-Française and was suppressed.
So popular were Favart and his troupe that the enemy became desirous of hearing his company and sharing his services, and permission was given to gratify them, battles and comedies thus curiously alternating with each other.