He was the 2nd but eldest surviving son and heir of Henry Northleigh (1612–1675)[3] of Peamore, Exminster, in Devon[4] by his wife Lettice Yard, a daughter of Edward[5] Yard of Churston Ferrers in Devon.
He was educated at King's College, Cambridge from 1660, and entered the Middle Temple in 1663.
[6] She was the granddaughter of Stephen Toller, haberdasher of Exeter, who in 1673 purchased "Crediton Parks", the former park of the Bishops of Exeter, from Sir John Chichester of Hall, Bishop's Tawton.
Susanna devised Crediton Parks to her daughter Susanna Northleigh, who devised it to her nephew John Tuckfield (c. 1719–1767) of Little Fulford, MP for Exeter, the eldest son of her sister Elizabeth Northleigh by her husband Roger Tuckfield of London, Merchant.
[7] By his wife he had children including: He died in 1694, as is recorded on his ledger stone in Alphington church, near Peamore.