Background
He was the eldest son and heir of Jonathan Rashleigh II (1642–1702), Member of Parliament, of Menabilly by his second wife Jane Carew, a daughter of Sir John Carew, 3rd Baronet (1635–1692) of Antony, Torpoint, Cornwall.
He was the eldest son and heir of Jonathan Rashleigh II (1642–1702), Member of Parliament, of Menabilly by his second wife Jane Carew, a daughter of Sir John Carew, 3rd Baronet (1635–1692) of Antony, Torpoint, Cornwall.
He served as Member of Parliament for Liskeard 1710-1722. He rebuilt Menabilly House circa 1710-1715. He was a supporter of the Jacobite Pretender.