Educated at the Middle Temple in 1679, Bertie first entered the House of Commons in 1685 in Boston, alongside his brother, Lord Willoughby de Eresby,[1] and generally inclined towards the Tories.
[2] In 1689, Bertie did not choose to stand for Parliament, and Sir William Yorke, a Whig, was returned alongside Lord Willoughby.
Peregrine did not obtain his brother's commission, but was rewarded with a Court appointment in 1692 as Vice-Chamberlain to Queen Mary, after Jack Howe was turned out of office.
Most of the Bertie family opposed the attainder; while it is unclear exactly what role Peregrine took, his conduct was sufficiently lukewarm to earn the severe displeasure of King William.
His office as Vice-Chamberlain was saved through the intercession of Sunderland, the Chamberlain, but the incident appears to have stimulated him to complete his transition from Tory to Whig.