Most active in Parliament during the 1670s, he and other members of his family were consistent political supporters of Bertie's brother-in-law, the Duke of Leeds throughout several reigns.
Lord Hatton reported seeing him in Paris that year, speaking in abusive terms of Charles II, and preparing to carry a message from the Duke of Buckingham to Cromwell.
He was named to committees involved with the suppression of Catholicism and Nonconformism, but most of his Parliamentary activity in the early 1670s was related to the Bertie family's interests, or local affairs in Lincolnshire.
In the general election of March 1679, Sir Richard Cust, formerly an ally of the Berties, and William Hyde obtained the support of the new Lord Exeter at Stamford.
[3] Peregrine's Horse Guards troop escorted the commissioners appointed by the new Parliament to disband the standing army through East Anglia in June 1679.
In 1680, he was removed as a commissioner of assessment in Lincolnshire and appointed a justice of the peace in the Parts of Holland and Lindsey, and he became a member of the Honourable Artillery Company in 1682.
He exchanged his post as a deputy searcher of customs for that of a surveyor of landwaiters in 1683, replacing the late Samuel Cust; he was succeeded by Edward Le Neve.
[1] After the dissolution of Parliament, Lindsey suggested that the corporation would return Charles and William Hyde, the latter's candidacy conciliating Lord Exeter's interest.
[3] Lindsey attempted to find a place for Peregrine at Grantham on the interest of the Earl of Rutland, who had married their niece Catherine Noel and was recorder of the town.
He was one of the minority of the House of Commons who concurred with the Lords that the flight of James II had not vacated the throne; otherwise, he showed little activity in this Parliament.
A Tory like the rest of his family, his role in this Parliament was overshadowed by his kinsmen, including his more active nephew and namesake, Peregrine Bertie.
The disaffection of Danby, now Marquess of Carmarthen, with the other Tory peers seems to have drawn the Berties, to some extent, into opposition to the Court during this time.
His will suggests that he was well-to-do when he died (Bridget and Mary each received dowries of £10,000), and on good terms with his brother-in-law Carmarthen, now Duke of Leeds.