Knightley, aged only five when his father died, became the ward of the latter’s ‘true and faithful friend’ (Sir) Thomas Smythe*, who promised to ‘bring him up in good learning’.
Knightley was first returned for Northamptonshire at the by-election for the third Jacobean Parliament occasioned by the ennoblement of Sir Edward Montagu*, thereby joining his stepfather, (Sir) Robert Bevill*, who was representing Huntingdonshire. With little more than a month before the prorogation, Knightley’s sole committee appointment was for a private bill concerning Sir Lewis Watson* (30 Nov. 1621).
Northamptonshire was predominantly a sheep-rearing county, and it was probably out of concern for the domestic wool industry that Knightley attacked the Merchant Adventurers on 22 April. The Company, having recently paid £50,000 to confirm their monopoly of cloth exports, attempted to pass the cost through to producers, but Knightley argued that ‘it was never known before that one subject should lay an imposition on another. He would have the merchants that gave the £50,000 bear the burthen of it, and not the commonwealth; for otherwise it would prove an ill precedent’.
Like Montagu, Knightley seems to have been on good terms with the royal favourite, the duke of Buckingham, to whom was perhaps introduced by his friend Sir John Eliot*.
Knightley sat again for the county in the first Parliament of Charles I. On 23 June 1625 he was named to a recusancy bill committee and ordered to attend a conference on the petition for a fast, and on the following day he was appointed to a committee to consider the heads of the petition on religion.
Although not recommended by the judges, Knightley was pricked as sheriff on the same day that judgment was given in the Star Chamber case. Lord Conway (Sir Edward Conway I*) informed Buckingham that ‘never was [a] man so perplexed, arguing that all the world would think it was a punishment laid upon him for my Lord Vaux’. He further reported that Knightley, protesting the ‘continued and sole dependence he had upon your grace ... declared his speeches and the endeavours he had used in the Parliament for the service of the king and the honour of you’; Knightley was clearly looking to Buckingham to ‘justify him and repair him well with the king and all the world’.
There is no evidence that Buckingham responded to Knightley’s appeals, and in any case Knightley, like Eliot, was rapidly becoming disillusioned by the favourite’s handling of the war and his ambiguous stance on religion. Together with many other Northamptonshire gentry, Knightley therefore openly resisted the Forced Loan, despite having been appointed a commissioner for its collection. He appeared before the Privy Council on 19 Jan. 1627, and was sent to the Fleet for refusing to kneel ‘lest, as they interpret it here, he should seem to acknowledge a fault, and crave mercy where he is not guilty’.
Unsurprisingly, Knightley’s committee appointments were dominated by religious measures such as the Sabbath bill (1 Apr.), and another for the deprivation of scandalous ministers (19 April).
Knightley maintained his friendship with Eliot, and after the latter’s incarceration in the Tower corresponded regularly with him, addressing him as ‘brother’ and assuring him that ‘my heart and affection you have always’.
Knightley died on 8 Nov. 1639 and was buried at Fawsley.
