7th United States Congress | regiment | Parachute Regiment (United Kingdom) | Regiment | Seventh Regiment Armory | Parachute Regiment | Foot Guards | Royal New Zealand Infantry Regiment | Michigan's 7th congressional district | Gloucestershire Regiment | Foot Locker | Devonshire Regiment | The Royal Canadian Regiment | Royal Newfoundland Regiment | Essex Regiment | East Yorkshire Regiment | Thousand Foot Krutch | Thomas Bruce, 7th Earl of Elgin | South Carolina's 7th congressional district | Royal Sussex Regiment | Royal Anglian Regiment | Paul Foot | King's Own Royal Border Regiment | James Stanley, 7th Earl of Derby | George Lascelles, 7th Earl of Harewood | Ferdinand Bonaventura, 7th Prince Kinsky of Wchinitz and Tettau | Cheshire Regiment | 5th Cavalry Regiment | William Keppel, 7th Earl of Albemarle | South Lancashire Regiment |
Campbell joined the army as an ensign of the 37th Regiment of Foot on 25 June 1771 and was appointed lieutenant in the 7th Fusiliers on 9 May 1774, serving in Quebec, where he was taken prisoner in the Siege of Fort St. Jean in 1775.