Born c. 1720, first son of William Cavendish, third Duke of Devonshire, and Catherine Hoskins. Married 1748 Charlotte Boyle, daughter and heir of Richard, second Earl of Burlington. Privy Councillor 1751–3; Master of the Horse 1751–5; Lord Treasurer of Ireland 1754–5 and 1761–3; Lord Lieutenant of Ireland 1755–6; Lord Lieutenant of Derbyshire 1756–64; First Lord of the Treasury 1756–7; Lord Chamberlain 1757–62. Died 2 October 1764.