The second son of Henry Ellison, of Hebburn, County Durham, and Henrietta, daughter of John Isaacson, he joined the 1st Regiment of Foot Guards as an ensign by purchase on 17December 1807. He became a lieutenant and captain on 20December 1812 then saw service at Cádiz, Spain in 1811 and during the Peninsular War from 1812–14. During the Waterloo Campaign he fought at Quatre Bras and Waterloo, for which he was promoted Brevet Major. At the latter battle he fought with the light companies at Hougoumont where "on one occasion, when he was forced to retreat from the orchard to the chateau, he would have been bayoneted by the French, had not the men, with whom he was a great favourite, charged back, and saved his life.