Knightley came of a family of Staffordshire origin which first represented that county in 1325. The Fawsley branch was established in 1415.
Knightley supported his colleague Sir Edward Montagu’s presentation of grievances to the Commons on the first day of business (23 Mar. 1604), and was named to the ensuing committee.
Knightley had returned to England by 9 Feb. 1605 when, together with his father and Montagu, he presented a petition from Northamptonshire with 36 signatures on behalf of deprived or suspended puritan ministers.
In the second session Knightley was appointed to a committee to consider how best to provide a learned ministry and prevent non-residence (22 Jan. 1606), and to attend conferences on the recusancy laws (3 Feb.) and ecclesiastical grievances (10 April). He was also named to committees for bills to enable Sir Christopher Hatton* to sell entailed property (4 Apr.) and to attaint the Gunpowder plotters (30 April).
Knightley invested in the Virginia Company, of which Smythe was governor, and the North-West Passage Company.
