Earl of Cardigan
Brudenell was the third son of the 3rd Earl of Cardigan and Elizabeth Bruce and a younger brother of the 1st Duke of Montagu and 4th Earl of Cardigan and the 5th Earl of Cardigan. He was educated at Winchester College and Oriel College, Oxford; on 27 January 1759, he married Anne Bishopp, a daughter of Sir Cecil Bishopp, 6th Baronet.