James Alexander Stewart-Mackenzie was a Scottish politician and British colonial administrator.

Vice-Admiral Keith Stewart was a Scottish Royal Navy officer and politician who sat in the House of Commons on two occasions. Having begun his naval career in around 1753, Stewart was promoted to commander in 1761 and then advanced to post-captain in 1762 because of political negotiations undergone by his father Alexander Stewart, 6th Earl of Galloway. Stewart commanded HMS Berwick at the Battle of Ushant in 1778 and in 1781 was appointed Commander-in-Chief, North Sea only to be superseded by Hyde Parker soon afterwards. As such he served at the Battle of Dogger Bank as a volunteer on Berwick.