On 26 April 1940, during the early stages of the Second World War, Gordon volunteered for overseas service, lying about his age to join the
Australian Imperial Force; falsely giving his middle name as Heather. Shortly afterwards, he married Myrtle Troy at St Edmund's Church of England,
Wembley Park, Perth, on 14 June 1940. On 12 July 1942, a plaque in his honour was unveiled in front of the Gingin Post Office; it was later moved to the town's war memorial. Later that year a portrait of Jim Gordon painted in 1941 by artist
William Dargie won the 1942
Archibald Prize, Australia's most famous portrait prize. Gordon returned to Australia in March 1942, now holding the rank of
corporal. While the 2/31st Battalion was soon deployed to Papua, a bout of malaria prevented Gordon from joining it until November 1942. He was promoted to
sergeant in July 1943. After seeing further action during the capture of Lae and the subsequent advance through the Markham and Ramu Valleys in New Guinea, he returned to Australia in January 1944. He was hospitalised due to malaria again, and was later reassigned to administrative duties. He remained in the Army until 17 February 1947. After discharge, Gordon briefly worked for the
State Electricity Commission, before rejoining the army as a regular soldier on 2 December 1947, achieving the rank of
Warrant Officer Class II in 1950. He continued service until 1 August 1968 when he retired; after this, he was employed at
Campbell Barracks (Western Australia), Swanbourne, as a groundsman until 1975. ==Later life==