Jack joined the unit on Timor as a Private from 2/40th Battalion, after the fall of Koepang, approx. March 1942. He was one of the former Koepang men, who moved to the village of Mape for intensive commando training and on 8 May 1942, they were formed into a new Platoon, “D” Platoon under the command of Lieutenant Turton and later under Lt Doig.
After the campaign on Timor, he embarked with the unit, for Australia aboard the Royal Dutch destroyer “Tjerk Hiddes” on either 11 Dec 1942 or 16 Dec 1942, as the embarkation rolls do not differentiate.
He transferred to 2/12th Infantry Battalion and was discharged on 30 Aug 1945.