The third Earl was a prominent statesman, ambassador and a Lord of the Admiralty. He married as his first wife Lady Amabel Grey, daughter of Henry Grey, 1st Duke of Kent. Their daughter Lady Jemima Campbell succeeded her maternal grandfather as Marchioness Grey in 1740. Through Lady Jemima this Lord Breadalbane was a great-grandfather of Prime Minister Lord Goderich. The third Lord Breadalbane outlived both his only son by his first wife and his two sons by his second marriage to Arabella Pershall. On his death in 1782 the male line of the first Earl failed.
