He was 20 years old and a corporal in the 7th Battalion, Australian Imperial Force during the First World War when he was awarded the VC for his actions on 9 August 1915, during the Battle of Lone Pine on Gallipoli, Turkey. During the action Turkish forces had made a determined counter-attack on the centre of the newly captured trench held by a lieutenant, Frederick Harold Tubb, two corporals (Alexander Stewart Burton and Corporal Dunstan), and a few men. The Turkish blew in the sand-bag barricade, leaving only a foot standing, but Tubb, Burton and Dunstan repelled them and rebuilt the barricade. Twice more the Turkish blew in the barricade and on each occasion they were repelled and the barricade rebuilt.