He is the oldest child and only son of the late James Campbell, 11th Duke of Argyll and Louisa Campbell, Duchess of Argyll. He lives with his family in their ancestral seat at Inveraray Castle in Argyll, Scotland. He's also a member of the House of Lords, in the Scottish Parliament. The Duke and his brother-in-law maintain close political relations for the benefit of both England and Scotland. He was part of the Better Together movement that supported the maintenance of Scottish alliance with the rest of the UK.
In 1997 he married Scottish aristocrat Ava MacTavish at Inverness Cathedral. The couple has two children:
- Michael Calum Campbell, Marquess of Lorne (b. 12 July 1999)
- The Lady Alice Maureen Campbell (b. 31 January 2002)