Strickland was subsequently a member of the nominated Barebone's Parliament and of both councils of state appointed by it. In 1654 he was made captain of the grey-coated foot-guards, who waited upon the Protector at Whitehall. This position gave him a prominent part in the second investiture of the Lord Protector. After the establishment of the Protectorate sat in the Parliaments of 1654 (for the East Riding) and 1656 (for Newcastle) and was a member of both councils of state established during Cromwell's rule. In December 1657 he was appointed to Cromwell's “House of Lords” — a "peerage" which of course did not survive the Restoration.