Devos was born in Mouscron, Belgium close to the French border. Both his parents were French and he moved to Tourcoing, France at the age of two. Seven years later, his family moved to Paris. During the Second World War he was sent, like many young men of his generation, to Germany to work. On his return to France, he took acting and mime lessons at the Étienne Ducroux school, where he met Marcel Marceau. In 1948, he was part of a burlesque trio (in the older sense of the word burlesque).
Devos' career took off in the 1950s when he began writing his own one man shows and was the opening act for Maurice Chevalier. Although his act still involved elements of his early years as a clown (such as juggling) he was mostly recognized because of his mastery of the French language. His unique brand of surreal humour and sophisticated puns garnered him much respect throughout the Francophone world. Devos is a leading character in Alejandro Jodorowsky's surrealist 1957 debut short film Les têtes interverties (a mime adaptation of Thomas Mann's 1940 play The Transposed Heads). He performed for the last time in 1999 in Paris' Olympia Theater.
Because he was born in Belgium, the nationality of Devos was often, and still is, a source of confusion. Some media reported his death by referring to "Belgian comic Devos" or "French and Belgian comic Devos". Devos was French and had a French passport, but was always respectful of his country of birth and once quipped that he was still, after all, a "fake Belgian".
He was awarded the Legion of Honor and the Académie française's Grand Prix du Théâtre.
