Jack Flemming enlisted into the Royal Artillery before volunteering for airborne forces shortly after the formation of No 1 Parachute Brigade during World War II.He attended Hardwick Hall for a month, which included two weeks of parachute ground training, before transferring to RAF Ringway for Parachute Training Course 20 which ran from 27 July to 3 August 1942.

On qualifying as a military parachutist he was posted to the 1st Parachute Battalion based at Kiwi Barracks in Bulford. 

He served with No 5 Section in No 6 Platoon of S Company during Operation Torch in North Africa.