Of Algerian Jewish descent, Atlan was born in 1913 in Constantine, French Algeria, and moved to Paris in 1930.

He studied philosophy at the Sorbonne and started as a self-taught painter in 1941. He was arrested for being Jewish and for his political activism in 1942.

Atlan pleaded insanity and was confined to the Sainte Anne asylum. He published a slim volume of poetry in 1944 and had his first exhibition at the Galerie Arc en Ciel.

In 1946 he met Asger Jorn and got involved with the CoBrA art group. His studio became a meeting place for the group in Paris.

In 1955 he exhibited in the Galerie Carpenter. He died in Paris in 1960 and is buried in the Cimetière du Montparnasse.