Jason Leslie Boyd Coulter was born at Ballarat, Victoria during 1877 to parents Irvine and Mary. A farmer by trade, he enlisted at Randwick, New South Wales under the name Jason Leslie Boyd on 27 August 1914. At the time Coulter enlisted, the upper age limit was set at 35 but he was 36 at the time. His age on enlistment was recorded as 35 and he was assigned to the 2nd Infantry Battalion.

Coulter departed Sydney aboard HMAT Suffolk on 18 October 1914. In March 1915, he was transferred to the 8 Infantry Battalion before being sent to Gallipoli. Coulter's brother, Lieutenant Colonel Graham Coulter, also served with the 8 Infantry Battalion and later commanded this unit.

Whilst at Gallipoli he was promoted through the ranks and achieved the rank of sergeant during August 1915. He also sustained severe gunshot wounds from his service in this campaign and died on 10 August 1915. Jason Coulter was 37 years old when he died and he is buried at the Alexandria (Chatby) Military and War Memorial Cemetery, Egypt.