[3] He was the brother of Mary Lillian Duke (who married his wife's brother, Anthony Joseph Drexel Biddle Jr.),[4] and first cousin to the flamboyant heiress Doris Duke.

By this marriage, which took place at Holy Trinity Church in Philadelphia, "one of the oldest and richest Philadelphia families was united with one of the richest families of the South.

Following the accidental discharge of his gun in 1905 during a hunting trip, his left arm was amputated below the elbow.

[1] In 1923, he drowned at Indian Harbor Yacht Club on Long Island Sound (near his summer residence in Port Jefferson),[1] when a boat overturned and he was unable to get back into the boat because of his missing hand.

[14] John Davidson portrayed Duke in the 1967 musical film The Happiest Millionaire.