He was the eldest surviving son of Sir Henry Innes, 5th Baronet (c. 1711–1762), and Anne Drummonda Grant (1711–1771).
The fight for the succession of the title encompassed seven years of constant litigation; according to one biography, "seldom have the lawyers met with a richer harvest.
The courts of Edinburgh and London have revelled in conflicting claims, and the House of Lords has been disturbed by never-ending appeals.
[6] Four years after his death, his widow remarried to Lt Col Walter Frederick O'Reilly, CB of the Royal African Corps, on 14 November 1827.
[7] Portraits of the Duke and his second Duchess were painted by Henry Raeburn, and hang in the entrance hall of the family seat of Floors Castle in the Scottish Borders.