In the Australian War Memorial website it shows that Leslie enlisted in the Royal Australian Air Force on 17 September 1943 at Sydney, NSW, Australia at age 26. His Service Number was 137133. At the time of his enlistment Leslie was living at Campsie in Sydney. His next of kin was shown as Doris Fortier, his wife. Leslie was discharged from the RAAF on 5 April 1946 in the rank of Leading Aircraftsman with the 3 Stores Depot. Leslie saw active service in Borneo/New Guinea.