Edward was the only child of Henry Hyde, 2nd Earl of Clarendon, and his first wife, Theodosia, daughter of Arthur, Lord Capel. His mother died when he was a toddler and, from the age of five, the family lived at Swallowfield Park in Berkshire, the home of father's new wife, Flower, daughter of the Rosicrucian Philosopher, William Backhouse. He was known, for most of his life, by his father's secondary title of Lord Cornbury and matriculated at Christ Church College, Oxford on 23rd January 1675.

In 1683, Edward entered the Royal Regiment of Dragoons as a Lieutenant-Colonel, becoming a Colonel two years later. He was also made Master of the Horse to Prince George of Denmark, husband of his cousin, the Princess Anne. In 1685, he was Page of Honour at the Coronation of his uncle, King James II and, in the same year, he was elected the Tory MP for Wiltshire, his family's ancient home. He held this seat for ten years, with only a brief lapse in 1688, the year of the Glorious Revolution in which he became one of the first commanders to desert King James, taking as many troops with him as a could. Macaulay, in his well-known description this event, describes Lord Cornbury as "a young man of slender abilities, loose principles, and violent temper," and attributes his treachery to the influence of Churchill. His Lordship subsequently sat for Christchurch from 1695 to 1701.

As a return for his desertion of King James II, William III appointed Cornbury Captain-General and Governor-in-Chief of of New York and New Jersey in 1701. He travelled to America where he apparently gained a reputation as the 'worst governor Britain ever imposed on an American colony'. He supposedly took bribes, plundered the public treasury and is said to have spent half of his time dressed in women's clothes. A popular story tells how he received the official world at Albany on the Queen's birthday dressed in female attire copied from the robes of his Royal mistress. A portrait, now hanging in the New York Historical Society, is even thought by many to represent Cornbury in this costume. While contemporary evidence of such outrageous conduct is distinctly lacking and largely based on rumour, he was recalled from New York in 1708 and immediately thrown into prison by his creditors. He remained there till the death of his father entitled him to be liberated as a peer. He was succeeded as Governor by John, 4th Lord Lovelace.

Notwithstanding his apparent delinquencies, Edward, 3rd Earl of Clarendon, was made a Privy Councillor on 13th December 1711, and Envoy Extraordinary to Hanover in 1714. Lady Theresa Lister wrote of him: "Edward Hyde, third Earl of Clarendon, presents one of those melancholy instances which too often occur amongst the descendants of distinguished men, where the name, the honours, the titles are reproduced, but unsupported and ungraced by any one of those qualities or virtues which won distinction for their ancestor. His conduct through life was a blot upon his name, and brought down upon him the scorn and reproach of two hemispheres."

Edward, 3rd Earl of Clarendon, sold Swallowfield Park to Thomas Pitt, commonly called 'Diamond' Pitt in 1719, and died, on 31st March 1723, at his house in Little Chelsea. He was buried in Westminster Abbey and was succeeded in his title by his first cousin, Henry Hyde, 2nd Earl of Rochester. The latter died in December 1753, when, his son (Henry Hyde, Lord Cornbury) having predeceased him, all his titles became extinct.

Partly edited from Lady Russell's 'Swallowfield & its Owners' (1901)