Bruce entered the Army at the age of seventeen, with the
purchase of a commission as ensign and lieutenant in the
Grenadier Guards on 18 June 1830. His promotion to lieutenant and captain was purchased on 22 February 1833. Bruce served as
adjutant of the regiment from 28 May 1835 until July 1836 and then on the staff of
Sir Edward Blakeney, the
commander-in-chief in Ireland. Bruce served as
military secretary to his brother Lord Elgin, the
governor of Jamaica, from 1841 to 1846, He acted again as military secretary to his brother from 1847 to 1854, during Elgin's term as
Governor-General of the Province of Canada, He returned to England in that year and served briefly as a surveyor-general at the
Board of Ordnance. and served until he retired as a lieutenant-colonel on the half-pay unattached list on 7 December 1858. ==Governor of the Prince of Wales==