Arthur Harrison enlisted into The Durham Light Infantry and later volunteered for airborne forces.After initial training at Hardwick Hall, he qualified as a military parachutist on Course 89 which ran at RAF Ringway from 28 October to 9 November 1943. The course instructor notes record that he was a "very good jumper, fine spirit, courageous."

He was posted to the 7th (Light Infantry) Parachute Battalion and served throughout its campaigns in North West Europe during 1944-45 and in the Far East, when it was deployed to Malaya, Singapore, Batavia and Semarang.

It is known that for much of this time he served with 9 Platoon in C Company, and it is possible that he served in the platoon at the same time as Ron Worthington who wrote letters home about their experiences in the Far East.