He was born in Bedhampton, Hampshire, England, the son of Rear-Admiral James Prevost and his first wife France née Haultain, and joined the navy in 1823 and by 1850 was a commander aboard HMS Portland, flagship of Rear Admiral Sir Fairfax Moresby, whose daughter (Ellen Mary) he married on 18 October 1842, they had five children:
- Ellen Louisa Prevost (1843–?)
- James Charles Prevost (1846–15 May 1920)
- Annette Prevost (1849–1916) married General Sir Henry John Thoroton Hildyard
- George Fairfax Prevost (1851–1940)
- Edward Augustan Prevost (1855–?)
Prevost became an admiral in 1880, and died in London in 1891.
Prevost Island in the Gulf Islands of British Columbia and other names on it, or nearby, e.g. James Bay and Charles Rocks, were named after him. Mount Prevost, near Duncan, and Prevost Hill, a landmark on Ten Mile Point at Cadboro Bay, British Columbia are also named for him.
He was the grandfather of General Sir Reginald Hildyard (1876–1965).
- For more on Rear-Admiral James Prevost see: O'Byrne, William R. (1849). . A Naval Biographical Dictionary. London: John Murray.
- The Plantagenet Roll of the Blood Royal: Mortimer-Percy Volume, Marquis of Ruvigny and Raineval, Reissued by Heritage Books, 2001 p. 309 ISBN 0-7884-1872-6 ISBN 978-0-7884-1872-3
- "Charles Rocks". BC Geographical Names.
- "James Bay". BC Geographical Names.
- "Prevost Hill". BC Geographical Names.