After his father's death, Favart simultaneously carried on his business as a pastry cook and wrote librettos for light operas. He became stage manager of the Opéra-Comique in 1743 and director of the company in 1758. His insistence that individual characters be costumed in a manner historically appropriate to their personalities and station, rather than in contemporary style, was an innovation that other directors were quick to imitate.

Favart's best play, Les Trois Sultanes (1761), is a comedy based on a love triangle. In it, song and dance play a less important part than in his other works, the best of which is La Chercheuse d'esprit (1741). Favart had a special talent for pastoral plays, one of which, Bastien et Bastienne (1753), was later given a musical setting by Mozart.