Mackenzie, who was born in Dundee, was the son of Sir Simon Mackenzie of Lochslin (died c. 1666) and Elizabeth Bruce, daughter of the Reverend Peter Bruce, minister of St Leonard's, and Principal of St Leonard's Hall in the University of St Andrews. He was a grandson of Kenneth, Lord Mackenzie of Kintail and a nephew of George Mackenzie, 2nd Earl of Seaforth.
Mackenzie was elected to the Faculty of Advocates in 1659, and spoke in defence at the trial of Archibald Campbell, Marquis of Argyll in 1661. He acted as justice-depute from 1661 to 1663, a post that involved him in extensive witch trials.
As Lord Advocate he was the minister responsible for the persecuting policy of Charles II in Scotland against the Presbyterian Covenanters. After the Battle of Bothwell Bridge in 1679 Mackenzie imprisoned 1,200 Covenanters in a field next to Greyfriars Kirkyard. Some were executed, and hundreds died of maltreatment. His treatment of Covenanters gained him the nickname "Bluidy Mackenzie". It has been argued that both he and Claverhouse kept to the letter of the law. It is unclear whether or not the epithet "Bluidy" is contemporary; it appears in The Heart of Midlothian (1818), given to Davie Deans. The language of blood prevails in the published testimony of Marion Harvey, hanged in 1681, who calls her blood onto Mackenzie: ""that excommunicate tyrant, George Mackenzie, the advocate", among others.
Mackenzie resigned for a short time in 1686, before taking up office again in 1688 and serving as shire commissioner for Forfarshire from 1688 to his death. He opposed the dethronement of James II, and to escape the consequences he retired from public life.
Mackenzie retired at the Glorious Revolution to Oxford. In London on 9 March 1690 he dined with William Lloyd and John Evelyn, two literary opponents from the past. He died at Westminster on 8 May 1691 and is buried in Greyfriars Kirkyard in Edinburgh, his mausoleum being designed by James Smith.
In private life Mackenzie was a cultivated and learned gentleman with literary tendencies. He published in 1660 Aretina, which has been called the first Scottish novel. He is remembered as the author of various graceful essays. A contemporary antiquarian, Alexander Nisbet, calls him "learned" and "renowned".
Mackenzie wrote legal, political, and antiquarian books, including:
- The Science of Heraldry, Treated as a Part of the Civil Law of Nations: Wherein Reasons are Given for its Principles, and Etymologies of its Harder Terms (1680);
- Institutions of the Law of Scotland (1684);
- Jus Regium: Or the Just and Solid Foundations of Monarchy in General, and More Especially of the Monarchy of Scotland: Maintain'd Against Buchannan, Naphtali, Dolman, Milton, &c. (1684), a major royalist tract;
- A Vindication of the Government in Scotland (1691);
- Antiquity of the Royal Line of Scotland (1686);
- Memoirs of the Affairs of Scotland from the Restoration of Charles II (1821).
Mackenzie took part in the Midlothian trials for witchcraft in 1661, and defended the alleged witch Maevia. He later wrote at length of his experience with witchcraft trials. He did not endorse the sceptical position, but stated that witches were fewer than common belief made out. He attributed confessions to the use of torture.
His Laws and Customs of Scotland in Matters Criminal (1678) was the first textbook of Scottish criminal law. In it Mackenzie defended the use of judicial torture in Scotland as legal. He said it was seldom used. In the aftermath of the Rye House Plot Charles II authorised the use of torture against William Spence, secretary to Archibald, Earl of Agyll, who was moved to Scotland. The Scottish privy council was reluctant, but eventually went beyond Scottish law in torturing Spence. Mackenzie visited William Carstares in prison in London, caught up in the same investigation, to warn him of the consequences of stubborn behaviour under questioning.
Other works were:
- Religio Stoici (1663);
- A Moral Essay preferring Solitude to Public Employment (1665);
- Moral Gallantry (1667); and
- The Moral History of Frugality (1691).
Mackenzie was the founder of the Advocates Library in Edinburgh. His inaugural oration there is dated 15 March 1689, so just before his departure south; but the evidence is that the oration was written some years before, and the library itself was operational from the early 1680s. The initiative followed Mackenzie's appointment as Dean of the Faculty of Advocates, in 1682.
George Mackenzie of Rosehaugh features as a character in John Galt's novel Ringan Gilhaize, or The Covenanters (1823).
- John (died young)
- Simon (died young)
- George (died young)
- Agnes, who married James Stuart, later 1st Earl of Bute
- Elizabeth, who married first Sir Archibald Cockburn of Langton and secondly the Hon Sir James Mackenzie of Royston, Bt.
- George, who married but died, without male issue, before his father
- Anne, who married Sir William Dick of Prestonfield
- Elizabeth, who married Sir John Stuart of Grandtully
- Patrick Cadell and Ann Matheson, editors (1989), For the Encouragement of Learning: Scotland's National Library 1689–1989, Edinburgh, HMSO.
- Lang, Andrew (1909). Sir George Mackenzie, King's Advocate of Rosehaugh: his life and times. London: Longmans, Green and Co.
- Mackenzie, Alexander (1879). History of the Clan Mackenzie. Inverness: A & W Mackenzie. pp. 115, 279. (also: available at "Schulers Books Online". Retrieved 14 August 2011.)
- Jackson, Clare (January 2007) . "Mackenzie, Sir George, of Rosehaugh (1636/1638–1691)". Oxford Dictionary of National Biographyedition=online. Oxford University Press. doi:10.1093/ref:odnb/17579. (subscription required)
- Lee, Sidney, ed. (1893). . Dictionary of National Biography. 35. London: Smith, Elder & Co. p. 142.CS1 maint: ref=harv (link)
- Scottish Covenanter Memorials Association. "Covenanters' Prison, Greyfriars Churchyard". Covenanter Memorials Association. Archived from the original on 23 October 2015. Retrieved 14 July 2016.
- The exact year of his birth is uncertain: his biography in the Dictionary of National Biography identifies the year as 1636, as does the biography published in the folio edition of his works (1716-1722), but he himself in his own work, The Religious Stoic, declared in 1663 that he was not yet 25 (Lang 1909, p. 22). "[He was born] either in 1636, as most sources assert, or in 1638, as his own works suggest" (Jackson 2007).
- Lang 1909, p. 21.
- Lang 1909, p. 25.
- (Jackson 2007)
- Lee 1903, p. 817.
- Cousin 1910.
- The field was later incorporated into Greyfriars Kirkyard and that section is known as the "Covenanters' Prison" (Scottish Covenanter Memorials Association)
- Bruce Lenman; J Mackie (28 February 1991). A History of Scotland. Penguin Books Limited. p. 315. ISBN 978-0-14-192756-5. Retrieved 26 February 2013.
- Andrew Lang (2005). Sir George MacKenzie: King's Advocate, of Rosehaugh, His Life and Times 1636(?)-1691. The Lawbook Exchange, Ltd. p. 2. ISBN 978-1-58477-616-1.
- Christ, Jesus (1794). A cloud of witnesses, for the royal prerogatives of Jesus Christ: or, The last speeches and testimonies of those who have suffered for the truth in Scotland, since 1680. p. 99.
- John Evelyn (1870). Diary and correspondence of John Evelyn. Bell and Daldy. p. 317.
- George Mackenzie (1 October 2005). The Laws And Customes of Scotland, In Matters Criminal: Wherein To Be Seen How The Civil Law, And The Laws And Customs of Other Nations Do Agree With, And Supply Ours. The Lawbook Exchange, Ltd. pp. iii note 4. ISBN 978-1-58477-605-5. Retrieved 26 February 2013.
- Alexander Nisbet (1816). A System of Heraldry. 1. Edinburgh: William Blackwood. pp. 152 & 329.
- George Mackenzie (1684). Jus Regium: Or the Just and Solid Foundations of Monarchy in General, and More Especially of the Monarchy of Scotland: Maintain'd Against Buchannan, Naphtali, Dolman, Milton, &c. By Sir George Mackenzie. heir of Andrew Anderson. Retrieved 26 February 2013.
- Kenneth G. C. Reid; Reinhard Zimmerman (2000). A History of Private Law in Scotland. Oxford University Press. p. 106. ISBN 978-0-19-826778-2.
- Darren Oldridge (2002). The Witchcraft Reader. Routledge. p. 219. ISBN 978-0-415-21492-6.
- Alex Sutherland (2009). The Brahan Seer: The Making of a Legend. Peter Lang. p. 61. ISBN 978-3-03911-868-7.
- Julian Goodare (2002). The Scottish Witch-Hunt in Context. Manchester University Press. p. 168. ISBN 978-0-7190-6024-3.
- George Fraser Black (2003). Calendar of Cases of Witchcraft in Scotland 1510 to 1727. Kessinger Publishing. p. 16. ISBN 978-0-7661-5838-2.
- Alexander Broadie (2010). The Scottish Enlightenment Reader. Canongate Books. p. 12. ISBN 978-1-84767-573-6.
- T C Smout (2005). Anglo-Scottish Relations from 1603 to 1900. Oxford University Press. pp. 79–8. ISBN 978-0-19-726330-3.
- Harris, Tim. "Spence, William". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/67376. (Subscription or UK public library membership required.)
- Daniela Havenstein (1999). Democratizing Sir Thomas Browne: Religio Medici and Its Imitations. Oxford University Press. p. 30. ISBN 978-0-19-818626-7.
- Cadell and Matheson, p. 1.
- Clare Jackson (2003). Restoration Scotland, 1660-1690: Royalist Politics, Religion and Ideas. Boydell Press. p. 27. ISBN 978-0-85115-930-0.
- Mackenzie 1879, p. 279.
- Lang 1909, p. 77,78.
- Armstrong, Ruth (8 November 2004). "Grave robbers steal skull in tomb attack". Edinburgh Evening News.
- Maclean, Diane (21 January 2005). "The tourist-terrorising Mackenzie poltergeist". Edinburgh Evening News.
- This article incorporates text from a publication now in the public domain: Cousin, John William (1910). "Mackenzie, Sir George". A Short Biographical Dictionary of English Literature. London: J. M. Dent & Sons – via Wikisource.