William Emanuel Baker was born in 1890 at Brunswick, Victoria, to parents George and Louisa. He served several years with the 63rd Infantry (East Melbourne) Regiment, rising to the rank of lieutenant before he enlisted for service during the First World War on 26 May 1916, aged 26. A telephone mechanic by profession, Baker enlisted with the 3rd Divisional Ammunition Column. He was initially allocated the rank of gunner and the service number 28471. On 25 October 1916, Baker embarked from Melbourne on the troopship HMAT Ulysses.
Baker arrived in England in December 1916 and was attached to the permanent staff of the Reserve Brigade Australian Artillery (RBAA). As a temporary sergeant, later promoted to extra-regimental sergeant, he remained with the RBAA until early December 1917. At this time he was deployed to France with the rank of gunner. Attached to the 4th Battery of the 2nd Field Artillery Brigade, Baker was promoted to the rank of acting bombardier in February 1918.
William Baker was killed in action in Belgium on 21 March 1918, aged 27, and is buried at Kemmel Chateau Military Cemetery, Belgium.