First World War Upon graduation from Duntroon in 1915, Chapman was commissioned as a
lieutenant in the
Australian Army. Volunteering for the
Australian Imperial Force (AIF), his first assignment was to
30th Battalion, Chapman, now a
captain, was wounded due to a gas attack in November, and this necessitated his evacuation to
England for treatment. He returned to the battalion in May 1917 as
adjutant and served in this capacity until October. Promoted to
major, he was attached to the
Australian Corps and 5th Division headquarters. During the
Hundred Days Offensive, he was acting brigade major of the 8th Brigade. He was later awarded the
Distinguished Service Order (DSO) for his actions of 28 August 1918, when he carried out a reconnaissance of the front lines under heavy fire.
Interwar period Chapman remained in the army after the cessation of hostilities, returning to Australia in June 1919. He married the following October, to Helena Mary de Booten, originally from
Chile. The couple would go on to have four children.
Second World War (left) talking with
Jessie Vasey and Lieutenant Colonels
George Vasey and John Chapman (right) on board the troop transport
Strathallan in December 1939. Still in England when the
Second World War broke out in September 1939, he was posted to the British
52nd (Lowland) Infantry Division as a staff officer but returned to Australia in January 1940, having been promoted to
lieutenant colonel in November 1939. Based in Melbourne, he was responsible for training at army headquarters before transferring to the reformed AIF in April 1940. Commencing on 8 June 1941, the division participated in the two-month-long
Syrian Campaign against the
Vichy French during which Chapman earned a recommendation for a
Bar to his DSO. This was duly gazetted and awarded in 1944. After the conclusion of the Syrian campaign, Chapman was promoted to temporary
brigadier in August and became responsible for the AIF Base Area in the Middle East. He later returned to Australia as deputy adjutant and Quartermaster General, based in
Brisbane. Promoted to major general in September 1942, he was appointed as
Deputy Chief of the General Staff in October 1944. He served in this capacity until March 1946. ==Postwar career==