Fane joined the 6th Dragoon Guards as a cornet in 1792 and served as "aide-de-camp" to the Lord Lieutenant of Ireland, John Fane, before obtaining a Lieutenancy in the 55th Regiment of Foot. He was promoted to Captain-lieutenant in the 4th Dragoons in 1795; to Major the following year and to Lieutenant-colonel in 1797, subsequently serving throughout the rebellion that year. On 1January 1805 following his removal to the Lieutenant-colonency of the 1st King's Dragoon Guards, he was appointed "aide-de-camp" to King George III, which made him a Colonel in the army.