|Member of Parliament for Wigtownshire|
|Preceded by||James Murray|
|Succeeded by||Andrew McDouall|
|Member of Parliament for Wigtown Burghs|
|Preceded by||Hon. Archibald Montgomerie|
|Succeeded by||John Hamilton|
|Died||3 March 1795(aged 55–56)|
Georgina Isabella d'Aguilar
(m. after 1782)
|Relations||John Stewart of Nateby Hall (grandson)|
|Children||James Alexander Stewart|
Leveson Douglas Stewart
|Parents||Alexander Stewart, 6th Earl of Galloway|
|Battles/wars||Battle of Dogger Bank|
Stewart was the second surviving son of Alexander Stewart, 6th Earl of Galloway and, his second wife, Lady Catherine Cochrane (the youngest daughter of John Cochrane, 4th Earl of Dundonald). Among his siblings were John Stewart, 7th Earl of Galloway, Hon. George Stewart (a Lieutenant who died at Fort Ticonderoga during the French and Indian War), Lady Catherine Stewart (wife of their cousin James Murray of Broughton), Lady Susanna Stewart (wife of Granville Leveson-Gower, 1st Marquess of Stafford), Lady Margaret Stewart (wife of Charles Gordon, 4th Earl of Aboyne), Lady Harriet Stewart (wife of Archibald Hamilton, 9th Duke of Hamilton), and Lady Charlotte Stewart (wife of John Murray, 4th Earl of Dunmore).
Stewart joined the Royal Navy in about 1753. He attained the rank of Captain in 1762, the promotion being one of the terms of his surrendering his seat in Parliament. He commanded HMS Berwick in 1777. He served under Admiral Keppel in the action off Ushant on 27 July 1778.
In June 1781, Stewart was given a North Sea command with the rank of Commodore. He served under Vice Admiral Hyde Parker in the Battle of Dogger Bank in August 1778. In September 1778, he was given command of the squadron blockading Dutch ports. Although he resigned this appointment after a ship escaped, Stewart was a highly regarded Naval officer and his career continued. He served under Admiral Richard Howe in his expedition to Gibraltar.
He represented Wigtown Burghs for a short time in 1762, between winning a by-election on 19 February 1762 and resigning before a new MP was elected on 15 April 1762. He was MP for Wigtownshire from 1768 to 1784.
On 13 May 1782, Stewart was married to Georgina Isabella d'Aguilar, daughter of Ephraim Lópes Pereira d'Aguilar, 2nd Baron d'Aguilar. Together, they were the parents of:
- James Alexander Stewart-Mackenzie (1784–1843), who married Mary Elizabeth Frederica Mackenzie in 1817. She was former wife of Vice Admiral Sir Samuel Hood and daughter of Francis Mackenzie, 1st Baron Seaforth. After their marriage, he assumed the additional surname of Mackenzie. Mary's younger sister, Helen Anne Mackenzie, was the wife of Joshua Henry Mackenzie, Lord Mackenzie.
- Keith Stewart-Mackenzie (1818-1881), married twice, first Hannah Hope-Vere, daughter of James Joseph Hope-Vere in 1844, second Alicia Bell in 1871, had issue by both.
- Mary Stewart-Mackenzie (1819-1913), married Philip Anstruther in 1838 and had issue.
- Caroline Stewart-Mackenzie (1822-1867), married John Petre in 1844 and had issue.
- George Stewart-Mackenzie (1824-1852), married Maria Marriott in 1850 without issue.
- Louisa Stewart-Mackenzie (1827-1903), married William Baring, 2nd Baron Ashburton and had issue.
- Leveson Douglas Stewart (1786–1819), a Lieutenant in the Royal Navy who married Elizabeth Dalrymple-Hay, daughter of Sir John Dalrymple-Hay, 1st Baronet and Susan Hay (daughter of Sir Thomas Hay of Park, 3rd Baronet), in 1808. They were the parents of several children, including.
- Keith Stewart, (1809-1822) died young, unmarried and without issue.
- John Stewart of Nateby Hall (1813-1867), married Elizabeth Thompson and had issue.
- George Stewart (1814-1893), married Mary Corrie in 1843 and had issue.
- James Stewart (1816-1895), married his first cousin, Sarah Dalrymple-Hay, daughter of Sir James Dalrymple-Hay of Park, 2nd Baronet and had issue.
- Susan Stewart (1819-1897), married Rev. George Charles in 1854. Without issue.
- Augusta d'Aguilar Stewart (1783-1836), who married her distant cousin, John Stewart, son of William Stewart of Castle Stewart and the Hon. Euphemia MacKenzie, daughter of Kenneth Mackenzie, Lord Fortrose in 1804
- Frederica Stewart (1806-1887), who married Major Edward Shalders in 1833 and had issue.
- "Galloway, Earl of (S, 1623)". www.cracroftspeerage.co.uk. Heraldic Media Limited. Retrieved 14 February 2017. CS1 maint: discouraged parameter (link)
- Marshall, John (1823). Royal Naval Biography : or Memoirs of the services of all the flag-officers, superannuated rear-admirals, retired-captains, post-captains and commanders, whose names appeared on the Admiralty list of sea officers at the commencement of the year 1760, or who have since been promoted; illustrated by a series of historical and explanatory notes. With copious addenda. Vol. I, Part II. London: Longman, Rees, Orme, Brown, and Green. pp. 444–446.
|volume=has extra text (help)CS1 maint: discouraged parameter (link)
- Wilkes, John (1811). Encyclopaedia Londinensis. p. 610.
- "Stafford, Marquess of (GB, 1786)". www.cracroftspeerage.co.uk. Heraldic Media Limited. Retrieved 5 June 2020. CS1 maint: discouraged parameter (link)
- "Aboyne, Earl of (S, 1660)". www.cracroftspeerage.co.uk. Heraldic Media Limited. Retrieved 5 June 2020. CS1 maint: discouraged parameter (link)
- "Hamilton, Duke of (S, 1643)". www.cracroftspeerage.co.uk. Heraldic Media Limited. Retrieved 5 June 2020. CS1 maint: discouraged parameter (link)
- "Dunmore, Earl of (S, 1686)". www.cracroftspeerage.co.uk. Heraldic Media Limited. Retrieved 5 June 2020. CS1 maint: discouraged parameter (link)
- McCulloch, Stuart (2017). A Scion of Heroes. Troubador Publishing Ltd. p. 65. ISBN 978-1-78462-793-5.
- "No. 13241". The London Gazette. 2 October 1790. p. 599.
- "The Hon. Keith Stewart (1739-1795)". threedecks.org. Retrieved 5 June 2020. CS1 maint: discouraged parameter (link)
- The Scots Magazine. Sands, Brymer, Murray and Cochran. 1795. p. 412.
- Admiralty, Great Britain (1870). The Navy List. John Murray. p. 326.
- History of Parliament: House of Commons 1754-1790, by Sir Lewis Namier and James Brooke (Sidgwick & Jackson 1964)
- "Baron d'Aguilar, Portuguese Baron of the Holy Roman Empire". www.twickenham-museum.org.uk. Twickenham Museum. Retrieved 5 June 2020. CS1 maint: discouraged parameter (link)
- thepeerage.com Admiral Hon. Keith Stewart
- Cumming, Constance Frederica Gordon (1904). Memories. Blackwood. p. 28.
- The Scots Magazine. Sands, Brymer, Murray and Cochran. 1821. p. 189.
- The Scots Magazine and Edinburgh Literary Miscellany. Archibald Constable & Company. 1808. p. 877.
- Booth (bookseller.), John (1817). The Battle of Waterloo: Also of Ligny, and Quatre Bras, Containing the Series of Accounts Published by Authority, British and Foreign, with Circumstantial Details Relative to the Battles, from a Variety of Original and Authentic Sources, with Connected Official and Private Documents, Forming an Historical Record by Those who Had the Honour to Share in the Operations of the Campaign of the Netherlands, 1815. J. Booth. p. 306.
- Leigh Rayment's Peerage Pages [self-published source][better source needed]
- Stewart family tree
|Parliament of Great Britain|
Hon. Archibald Montgomerie
| Member of Parliament for Wigtown Burghs
| Member of Parliament for Wigtownshire