 In 1939 he joined the army and played the tuba and saxophone in the army band.He stayed in the army until the 1950s; during the presidency of Paul Magloire he left the military and joined the band at the National Palace.In 1968, with the encouragement of his friends Préfete Duffaut and Pierre-Joseph Valcin and the help of the Centre d'Art in Port-au-Prince, Grégoire began painting.