 Among his siblings were Lady Cecilia Underwood (the second wife of Prince Augustus Frederick, Duke of Sussex, the sixth son of King George III).From his father's first marriage to Catherine Annesley (the only daughter of the 1st Viscount Glerawly), his half-siblings included Arthur Gore, 3rd Earl of Arran, Lady Anne Jane Gore (the third wife of John Hamilton, 1st Marquess of Abercorn), and Lady Catherine Charlotte Gore (wife of John Evans-Freke, 6th Baron Carbery).His paternal grandparents were Arthur Gore, 1st Earl of Arran (eldest son of Sir Arthur Gore, 2nd Baronet) and the former Jane Worth (widow of William Worth of Rathfarnham).