Jean Louis Forain was the son of a painter and decorator and was apprenticed to a visiting card engraver. He studied briefly under Gérôme and Carpeaux at the École des Beaux-Arts in Paris and regularly visited the Louvre, where he copied works by the masters. It is said that for a time he made a precarious living by selling small drawings in the style of Grévin. He went on to collaborate on various publications as a draughtsman and columnist, starting in 1876 on La Cravache and then collaborating on the newspapers Le Journal Amusant, Le Figaro and L’Écho de Paris. This introduced him to the diverse worlds of Paris society – the world of the theatre, of shows, and of literature – where he wryly noted the habits and shortcomings particular to each. This led him to follow a route very characteristic of this period, already seen in the work of Steinlen, Caran d’Ache and Toulouse-Lautrec in the journals La Pléiade, La Vogue and La Revue Blanche.

In addition to his many collaborations on magazines and journals of the period, Jean Forain produced etchings and 99 lithographs, including some posters. Some of the albums of drawings he published contain series: La Comédie Parisienne, a series of 250 drawings, and Les Temps Difficiles, a series of 99 drawings. He also illustrated literary works, including: Les Pantins de Paris by Gustave Coquiot in 1920 and Les Tribunaux by Georges Courteline, 1931. He also collaborated on the illustration of La Vraie Tentation du Grand Saint Antoine, 1880, by Paul Arène, Chansons Fin de Siècle, 1891, by J. Oudot and Montmartre Immortel, 1922 by E. Bayard.

He exhibited with his Impressionist friends Monet and Degas at the official Salon in 1884 and 1885 and, according to some sources, also in 1879, 1880 and 1881.