Harley was born in Brampton Bryan Castle, Herefordshire, the son of Sir Robert Harley, KB, and his third wife Brilliana, the daughter of Edward Conway, 1st Viscount Conway. He was educated at Gloucester, Shrewsbury School and Magdalen Hall, Oxford. He was a student of Lincoln's Inn in 1641. In 1642, he took up arms in the Parliamentary cause against the King in 1642, though disapproving of military supremacy in the nation. He was shot in the arm during a skirmish in Gloucestershire in August 1644. In 1646 he was elected Member of Parliament for Herefordshire as a recruiter to the Long Parliament and was excluded in 1648 under Pride's Purge. In 1656 his father died and he inherited his estates, he was also elected MP for Herefordshire again in the Second Protectorate Parliament. He was elected MP for Herefordshire again in 1660 for the Convention Parliament. At the Restoration, Charles II made him Governor of Dunkirk in 1660. He was elected MP for Radnor in 1661 for the Cavalier Parliament and was re-elected in February 1679 for the First Exclusion Parliament. In the second election of 1679 he was elected MP for Herefordshire again, and was re-elected in 1681. He supported the revolution of 1688 and was re-elected for Herefordshire in 1689, in 1693 and 1695. Harley was a conscientious upholder of the rights of the people, who showed their appreciation by sending him continuously to Parliament. Though a churchman himself, he fought against any form of persecution of the dissenters, was without party prejudice, and was remembered more for his practical benefactions than for such theoretical performances as A Scriptural and Rational Account of the Christian Religion.
Family
Harley was married twice. On 26 June 1654 he married, Mary, daughter and coheir of Sir William Button of Parkgate, Tawstock, Devon. They had four daughters, one of whom was called Elizabeth. On 25 February 1661 he married Abigail, daughter of Nathaniel Stephens of Eastington, Gloucestershire. They had four sons and one daughter, Abigail. He had two notable sons Robert and Edward.
