William enlisted in April 1915 at Lismore NSW stating that he was twenty years of age and born in London England. He gave the name of his sister Miss G O’Brien, 21 Ramilliers Street, Tower Hill, London as his next of kin and his Australian address as care of Lewin Bros. ‘Clinton’ Inverell.
William joined the 26th Battalion, A Company, and left Australia the following month on the ship HMAT A11 Ascanius. He served at Gallipoli until becoming ill and was then sent to hospital in Malta.
At the end of 1915 he was returned to Australia where he re-enlisted in April 1916 at Chermside, Queensland and was sent to England. In early September he went to France where the following year he was wounded in action. After three weeks he rejoined his battalion and in July was promoted to Corporal.
Wiliam was killed in action on 8 August 1918 and buried at Villers-Bretonneux Military Cemetery, Fouilloy, France.