John George Cosson was born at Barnes, England during 1866 to parents John and Eliza. He immigrated to Australia at the age of eight and married Elizabeth Mackenzie in 1900. A tobacconist by trade, he enlisted at Perth on 12 May 1915. At the age of 49, he joined the 16th Infantry Battalion with the rank of private and departed Fremantle aboard HMAT Chilka on 18 June 1915. Two nephews, Private Frederick Arthur Kinsey and Private Harry Cosson, also served during the First World War.

Cosson was wounded at the battle of Lone Pine on 7 August 1915 and re-joined his unit during October 1915. Cosson was still at Gallipoli for the evacuation and was amongst the last 22 men to leave. On 1 January 1916, he was promoted to the rank of corporal and four months later transferred to the 48th Infantry Battalion. It was also at this time that he became a second lieutenant. During 1916, Cosson also received a mention in despatches and was awarded the Distinguished Conduct Medal. John Cosson was 50 years old when he was killed in action at the battle of Pozieres on 7 August 1916 and he is commemorated on the Villers-Brettoneux Memorial.