As sheriff of Oxfordshire in 1634 he was charged with the duty of collecting the levy of ship money, in which he encountered popular opposition.
He was MP for Tamworth in the Long Parliament, but refused to act as a commissioner for the trial of Charles I.
[1] On the overthrow of Richard Cromwell, Wentworth returned to his place in the Long Parliament, and on 10 January 1660 lodgings were assigned to him in Whitehall by the Council of State.
[2] Sir Peter, who was a friend of John Milton, died on the 1st of December 1675, having never been married.
By his will he left a legacy to Milton, and considerable estates to his grand-nephew Fisher Dilke, who took the name of Wentworth.