John Mannion enlisted in The East Yorkshire Regiment before volunteering for airborne forces in March 1943.
Cpl Mannion attended parachute training course 59 at RAF Ringway. The course ran from 5 to 16 April 1943 and comprised a course cadre of 188 trainees. The course report records 'Cpl Mannion: Jumped well without hesitation. Average performer.’
On completion of his parachute training Cpl Mannion served with the 6th (Royal Welch) Parachute Battalion. He went on to serve in Italy on Operation Hasty and in the south of France, Greece and Palestine.
Sgt Mannion was demobilised in January 1946.