Background
He was the eldest son and heir of Sir John IV Killigrew (d1584) of Arwenack, Captain of Pendennis Castle, Member of Parliament for Lostwithiel 1563 and for Penryn in 1571 and 1572, (elder brother of Henry Killigrew (c1528-1603), Member of Parliament and diplomat and of William Killigrew (d1622), Member of Parliament and Chamberlain of the Exchequer) by his wife Mary Wolverston, daughter of Philip Wolverston of Wolverston Hall, Suffolk.