William Belcher was born in Ballarat and was a Butcher by trade when he enlisted in the 12th Battalion, 5th Reinforcement on 4 March 1915 at the age of 28. His unit embarked from Melbourne, Victoria, on board HMAT A20 Hororata on 17 April 1915. On 26 July 1916 he received a promotion to Lance Corporal. He was awarded a penalty of two days' pay for being absent without leave from Tattoo Roll Call on 3 September 1916 and was reverted to Corporal, but received another promotion to Acting Sergeant on 4 January 1917. After some trouble in February 1918 he was reverted to a permeant rank of Private before returning to Australia on 14 December 1918 aboard the SS Burma.

Tree No. 3067