Gabriel Yacoub was born in Paris, of a Lebanese father and a French mother. He was a guitarist and singer with the Alan Stivell group that toured France in 1971. Before he founded Malicorne, Gabriel and Marie Yacoub recorded Pierre de Grenoble (1973). Indeed this was originally intended to be the name of the group. It included contributions from Dan Ar Braz. With Malicorne, Gabriel played acoustic and electric guitar, mandolin, epinette de Vosges and banjo, while Marie played electric dulcimer, bouzouki and hurdy-gurdy. They sang most of the lead vocals on the albums. In 1978, while Malicorne were at their peak, Gabriel recorded a solo album called trad.arr, which featured English fiddler Barry Dransfield as guest.
In the final year of Malicorne, 1986 Yacoub recorded Elementary Level of Faith. This was highly experimental, with Yacoub's own compositions and electronic effects. Warm emotions are combined with industrial sounds. It is very much a companion-piece to Malicorne's Les Cathedrales de L'Industrie.
After a four-year gap he toured as a duo with Marie. He released Bel which had a string quartet on it and bagpipes from Jean-Pierre Rasle (who had previously recorded with The Albion Country Band). By the time of Quatre (1994), he had appeared on 15 albums. Bel and Quatre are sometimes considered to be his best solo albums, with beautiful arrangements of his own songs and contributions from harper Alan Stivell.
He finally recorded an album of his songs in English in 2002, The Simple Things We Said. It had a stripped-down sound of voice and guitar.
He has written a book of poetry and lyrics, called Les choses les plus simples.