A Cornish borough seat was arranged for Killigrew about the time he attained his majority. He left no mark upon the records of the 1601 Parliament. On 31 Oct. 1601 John Chamberlain wrote:
Here is much jostling and suing for places in the privy chamber, by reason that most of them, being grown old and weary of waiting, would fain bring in a successor, as Master Killigrew his son
and Killigrew succeeded to his father’s court career. He died, a wealthy man, between 20 Sept. 1632, when he made his will, and 12 July following, when it was proved.