In 1704, he married Mary, the daughter of John Norborne of Great Stukeley, by whom he had four children:
Charles Bertie (d 13 September 1754), married Bathsheba Mead, daughter of Richard Mead. Had four sons, Charles, Richard, James, and Review Montagu, all of whom died without issue.
Norborne Bertie (d 1779), no issue
Peregrine Bertie (1709–1777), married Elizabeth Payne in 1736, had several children including Albemarle Bertie, 9th Earl of Lindsey
Susan Bertie, married Edward Hales, second son of Sir Edward Hales, 3rd Baronet
Bertie was politically active from 1702, when he became a freeholder of Northamptonshire, and helped rally the Tories of that county under the tutelage of his father. He followed his half-second cousin, Lord Abingdon, in opposing the French commerce bill which was defeated in 1713, despite the support of the Tory Harley Ministry. However, Bertie was otherwise identified with the Tories and was in opposition to the Townshend Ministry, voting against the Septennial Acting.
3rd Parliament of Great Britain. 6th Parliament of Great Britain. 5th Parliament of Great Britain]
After the death of his father in 1711, he succeeded him as Member of Parliament for Stamford.
