Newton was the son of William Legh, 1st Baron Newton, and Emily Jane Wodehouse, daughter of the Venerable Charles Nourse Wodehouse, Archdeacon of Norwich.
Newton's parentage involved his father, William Legh, 1st Baron Newton, and his mother, Emily Jane Wodehouse, who came from a notable family, being the daughter of the Reverend Charles Nourse Wodehouse, Archdeacon of Norwich.