Killigrew stood for the open borough of Camelford at the general election of 1660, and was seated with Samuel Trelawny on the merits of the return. He was classed as a friend by Lord Wharton, but he made no recorded speeches in the Convention and was appointed to no committees before the election was declared void. He did not stand at the by-election, nor did he sit again, though he lived for another 45 years. He was active in local affairs, and seems to have enjoyed a measure of royal favour. He hoped to succeed his father as MP for Helston in 1668, but his interest could not prevail against his fellow-courtier Sidney Godolphin I. He continued to receive his father’s £300 p.a. pension, which had been extended to cover his life. In 1673 he and John Tregagle were appointed joint receivers of the duchy of Cornwall for life, although by a private agreement he was to receive up to £300 a year out of the office and leave its functions, salary and profits to Tregagle. In the following year he took part in an investigation into the coinage of tin and the laws of the stannaries. He continued his father’s efforts to develop Falmouth, where, by 1676, a neew quay had been built, to which, depsite their strong opposition, the neighbouring ports of Truro, Penryn and Helston had to bring most of their goods.
Killigrew remained on the Cornish commission of the peace in 1680 and was presumably opposed to exclusion. In June 1688, he was marked as ’absent’ in the returns of the royal agents on the answers to the questions on the Test Act and Penal Laws, and his name was not included in the list of proposed justices of the peace. In 1697 he was reprimanded for failure to render any account of duchy revenues since the Revolution. He retired to Ludlow, but in 1702 he was found to be £3,133 in debt to the crown, and proceedings were commenced against him. He died on 8 Jan. 1705, aged 71, and was buried at Falmouth. His son had been killed in a duel by Walter Vincent II, and Arwennack was inherited by his daughter, whose husband, Martin Lister, assumed the name of Killigrew and wrote a history of the family.