Prior to the war he worked on the staff of the local newspaper, the Kalgoorlie Miner.
On the outbreak of WWII, John was a Corporal in the 28th Battalion, Militia, with service No 460230. He was offered a commission in the A.I.F. but declined, as he wanted to join the R.A.A.F. The application to join the R.A.A.F. was rejected for health reasons (enlarged heart), and he continued serving with 28th Battalion now with service No W29791. He was discharged from the Militia on 6 Sept 1940.
He joined the A.I.F. on 29 Apr 1941, completed his commando training and was an original member of the unit, embarking aboard “S.S. ZEALANDIA” on 8 Dec 1941 for Timor as a Lance Sergeant in No 1 Sect, “A” Platoon.
Nov 1942 he was commissioned in the field and took command of No 9 Sect.
After the campaign on Timor, he embarked with the unit, for Australia aboard the Royal Dutch destroyer “Tjerk Hides” on either 11 Dec 1942 or 16 Dec 1942, as the embarkation rolls do not differentiate.
He was Mentioned in Despatches, London Gazette, 25 May 1943 and in the Commonwealth of Australia Gazette, No 119-3 Jun 1943. These are the two Gazettes for the Timor Campaign.
After leave and reorganization he embarked with the unit for New Guinea as a Lieutenant, Officer Commanding, No 9 Sect, “C” Troop, aboard S.S. “DUNTROON” on 17 Jun 1943. The unit was involved in the patrolling of the 350-mile (570Km) front along the Bismarck Range and during one of the many patrols he led, he was awarded the Military Cross, London Gazette, 9 May 1944 and in the Commonwealth of Australia Gazette, No 81-27 Apr 1944.
After the New Guinea Campaign, he returned to Australia with the unit aboard “TAROONA” on 3 Sept 1944.
Transferred to 2/7 Cav Cdo Sqn, 1 Nov 1943.
John was discharged on 27 May 1946.
He was the founding President of the 2/2 Commando Association, a position he held for 2 years until his job transfer to the country.
Jack passed away on the 13 Oct 1969, aged 53.
“Commanded a party which made a daring night raid on strongly held enemy positions at “KILAU” N.G. During the night 10/11 Jan 1944, Lieut Denman led his men right into the enemy defences unobserved and exploiting the element of surprise to the utmost inflicted numerous casualties. During the withdrawal one man was badly wounded and unable to walk or crawl clear. Lieut Denman ignoring his own danger and in the face of heavy enemy fire went back to the wounded man who was lying within 20 Yds of the enemy and dragged him to safety over open ground which was continually swept by heavy small arms and mortar fire. Lieut Denman displayed great gallantry in the face of the enemy to rescue a badly wounded man. He has consistently shown outstanding courage under fire. ” Note. 20 Yds means 20 Yards, which equates to approx. 18 Metres