Born to a Corsican father in Montpellier and a mother active in the Résistance, in the Hérault département of southern France. Involved also she was caught but not deported for its young age. She was raised by her maternal grandparents. She moved to Saint-Germain-des-Prés in Paris in 1946 after her mother left the country for Indochina with the French Navy.

Juliette Gréco came to be one of the stars of the bohemian "in" crowd of post-war France. She encapsulated the disenchantment and poverty of the French intellectuals following World War Two in her person. She dressed in all black and let her long black hair hang free, creating an Ophelia-like look of having just drowned.

A famous description of Juliette Gréco is that her voice "encompasses millions of poems". She was the muse of many of the writers and artists working in Saint-Germain-des-Prés, such as Jean-Paul Sartre and Boris Vian. Some of these artists would write songs for her to sing.

She fell in love with and almost married Miles Davis when he visited Paris in 1949.