In the late 1800s, museum officials at the Louvre in Paris discovered a signature on a painting long thought to be by the great Dutch artist Frans Hals. While cleaning The Jolly Companions, they found that the surprising signature read "Judith Leyster" (lie-stir), not "Frans Hals."

Leyster, the "mystery artist" behind The Jolly Companions, had been born about 250 years earlier in the Dutch city of Haarlem. At a time when women seeking art careers were often helped by artist fathers, Leyster—a brewer's daughter—had to rely on talent alone. By the age of 17, she had gained a reputation as an artist of great promise, and at age 24 she was elected to the painters' Guild of St. Luke. She taught painting for several years before she married another painter, Molenaer, in 1636 and moved to Amsterdam. After her marriage, she produced fewer and fewer paintings.

Leyster's work has often been compared with that of Frans Hals, the artist originally assumed to have painted The Jolly Companions. Hals was a friend of Leyster's. She learned from the elements of his technique, especially his brushwork. Leyster turned to other artists as well. She heard about Caravaggio's use of light and dark to heighten drama in a painting and experimented with the effects of light in her paintings throughout her career.