Paton steadily rose through the ranks and at the outbreak of the First World War was appointed to command the Newcastle Defended Port.

Paton took over the 7th Brigade on 15 October 1915 on direct orders from Major General James Gordon Legge.

On 5 November, while directing an attack on a trench known as "The Maze", Paton was wounded by a German sniper and evacuated to England.

On 24 August 1918 following frustration at being passed over for divisional command multiple times, Paton elected to retire and returned to Australia.

Paton returned to service after the war and commanded the 5th and 1st Brigades, and then the 2nd Division, retiring in 1926 with the rank of major general.