Henri began playing in the band at the wallpaper factory where his father worked, and also performed in silent film soundtracks beginning at age 14.
At the outbreak of the Second World War in 1939, Akoka was sent to a military orchestra in Verdun, where he met Étienne Pasquier and Olivier Messiaen.
While they were awaiting transport to a German prison camp, Akoka sight-read Messiaen's composition "Abîme des Oiseaux" for solo clarinet, though he "grumbled" about its difficulty.
[3] It was for this ensemble that Messiaen composed his Quatuor pour la fin du temps, premiered in the camp in January 1941.
[5] Akoka's release from the camp was arranged by Karl-Albert Brüll, a guard who provided false papers for Messiaen.