The fourth son of John Stuart, 3rd Earl of Bute and Mary Wortley Montagu, he was born in Kenwood House, London.

His two sons were born after his return from America: He had several notable brothers and sisters, including John Stuart, 1st Marquess of Bute (1744–1814); The Most Rev.

He had been elected MP for Bossiney in 1776, succeeding his elder brother Lord Mount Stuart, who had been created Baron Cardiff.

[6] However, his pride and violent temper led him to quarrel with Lord Hood, commanding the Mediterranean Fleet, and with the civilian viceroy of Corsica, Sir Gilbert Elliot, Bt.

[1] In 1798, he was sent to attack Menorca (historically called "Minorca" by the British) with 3,000 men, an appointment heartily approved by Lord St Vincent, who praised Stuart as an excellent general and inspiring leader of troops.

Though unequipped with siege artillery, he successfully dissimulated and bluffed the Spaniards into surrendering the island without loss of life, an exploit for which he was made a Knight of the Bath.

In March 1799, he responded to an appeal by Admiral Nelson (who, like St Vincent, thought him an excellent leader), and brought the 30th and 89th Regiments under Colonel Blayney to Palermo, from whence they were dispatched to secure Messina against French invasion.