He was born in County Meath, son of John Netterville of Dowth and Alison St Lawrence, daughter of Nicholas St Lawrence, 4th Baron Howth.[1] His family had a long association with the law: the first recorded member of the family in Ireland was Nicholas de Netterville, who was appointed a judge of the Court of Common Pleas (Ireland) in 1301. John's cousin and brother-in-law Thomas Netterville was a judge of the Court of King's Bench (Ireland), and after John's death his widow remarried yet another High Court judge, Sir Patrick White.[2]