Harley was the son of
Sir Robert Harley and his third wife
Brilliana, the daughter of
Edward Conway, 1st Viscount Conway. He was educated privately under Mr Simons. During the English Civil War, he served in the Parliamentary Army from 1643 to 1647. He was appointed
Steward of the King's Manors or lordship of Cantref
Moelynaidd, and of the boroughs of
Knighton and
Presteign, Radnorshire. Harley married Edith Hinton, widow of Thomas Hinton of Hayton, Shropshire and daughter of Thomas Pembrugge of Wellington. He was the brother of
Sir Edward Harley. ==Political career==