Portal was born in Bayonne on 27 November 1935. His family was musical and there were several instruments in his house when he was growing up. His interest in jazz began after hearing it on the radio after World War II. He studied clarinet at the Conservatoire de Paris and conducting with Pierre Dervaux.
Portal “gained experience in light music with the bandleaders Henri Rossotti and (in Spain in 1958) Perez Prado, as well as with the drummer Benny Bennett (1960), Raymond Fonsèque (1963), Aimé Barelli, and, for many years, the singer Claude Nougaro”.
Portal co-founded the free improvisation group New Phonic Art.During 1969, Portal played on a recording of Karlheinz Stockhausen’s Aus den sieben Tagen.
Portal began scoring music for films in the 1980s.He has won the César Award for Best Music Written for a Film three times.