Born as Armand Fernandez in 1928 in Nice. He was the son of an antique dealer. In 1946 he began to study painting in Nice and in 1947 met Yves Klein and Claude Pascal in Paris and accompanied them on a walking tour of Europe. Later he enrolled as a student in Paris where he concentrated on archaeology and oriental art. His pictures were influenced by Surrealism.

In 1951 he became a teacher at the Bushido Kai Judo School and completed his military service as a medical orderly in the Indo-Chinese War.

He did abstract paintings in 1953. He took part in projects with Yves Klein concerned with Zen Buddhism and astrology. He was impressed by a Kurk Schwitters exhibition in Paris in 1954 which inspired him to start work with stamp imprints. He had occasional jobs, including selling furniture and harpoon fishing.

He had his first one-man exhibitions in London and Paris in 1956. In 1958 he dropped the 'd' in his name, as the result of a printer's error. His first works in 1959, called Accumulations were assemblages of everyday objects and similar consumer articles, displayed in boxes. The Poubelles used collections of rubbish. In 1960 he became a founding member of the Nouveau Realistes. He showed in New York and Milan in 1961 and made his sliced and smashed objects. He started his so-called Combustions, or burned objects in 1963. After 1964 polyester became his most important material. He worked with the company Renault in 1967 and represented France at "Expo '67", Montreal. In 1970 he started his Accumulations in concrete. Later he began a series with organic garbage embedded in plastic. Since 1975 he has lived in New York, where he has a studio, and in Paris.