His father and brothers were active in the Royal service after the Restoration, and Berkeley himself was a Page of Honour to King Charles II from 1668 to 1672.
He fought at the Battle of Sedgemoor in 1685 and was made colonel of his own regiment of Dragoons (later the 4th Queen's Own Hussars) from 1685 to 1688 and from 1688 to 1693.
He sometime married Barbara, the daughter of Sir Edward Villiers, Knight Marshal of the Royal Household.
In 1702, he was appointed Treasurer of the Chamber to Queen Anne and in 1703 his wife was granted a pension of £600 p.a, having been governess to the late Duke of Gloucester.
He was returned unopposed at the 1705 English general election and voted for the Court candidate for Speaker on 25 October 1705.
[1] Fitzharding died, with the title, at Windsor of palsy on 19 December 1712 and was buried in Westminster Abbey.