On ‘Ulster Day’, Saturday, 28th September 1912, Paul signed the Ulster Covenant at Coleraine Guild Hall.
At the age of 20, Paul volunteered and enlisted into the 6th Bn. Black Watch as a Private. He served the British Expeditionary Force and was later promoted to Lance Corporal, Corporal, Sergeant and Acting Quarter Master Sergeant.
Service was seen in Festubert 1915, Somme 1916 and Peronne 1918.
Paul was injured 3 times; gunshot wound to the leg, gunshot wound to the shoulder and neck and gassed.
He was demobilised in February 1919. He was awarded the 1914/15 Star, the British Victory Medal and the British War Medal.
Following demobilisation, he rejoined the Northern Bank on 24th October 1914 at Head Office.
Transfers followed to Connswater (1919), Strabane (1919), Carrickfergus (1920), Newry (1922), Head Office (1922), Newry (1923), Head Office (1924), Omagh (1925), Donegall Square (1927), Head Office (1928) and Ballymena (1928).