 His sister was Cynthia Mary Burns, the first wife of Sir John Carew Pole, 12th Baronet.His father was a nephew of the prominent American banker J. P. Morgan and a grandson of Junius Spencer Morgan.His maternal grandparents were American heiress Elizabeth Livingston Cavendish-Bentinck (a daughter of Maturin Livingston Jr.) and William George Cavendish-Bentinck MP (a son of George Cavendish-Bentinck MP).