 He was the son of Hugh Dudley Auchincloss Sr. (1858–1913), a merchant and financier, and Emma Brewster Jennings.His maternal grandparents were Oliver Burr Jennings and Esther Judson Goodsell.His uncles included Edgar Stirling Auchincloss, the father of U.S. Representative James C. Auchincloss, and John Winthrop Auchincloss, the grandfather of Louis Auchincloss, an attorney and author.