[2] Coulter grew up the son of a sugarcane planter in the Danish West Indies and was sent to live in Scotland in 1894.
[2] After leaving school, Coulter served an engineering apprenticeship and prior to the First World War, he worked in the drawing office at Fairfield Shipyard.
[2] By spring 1915, half a year after the outbreak of the First World War, Coulter had enlisted in the Highland Light Infantry.
[2] He was commissioned as a temporary second lieutenant on 28 September 1915 and was awarded the Military Cross for actions on 7 February 1917:[3] For conspicuous gallantry and devotion to duty during a raid on the enemy's trenches.
He led his men with great dash and the success of the raid was largely due to his personal coolness and initiative.