Newton was born in Ohio County, Kentucky, to Nicholas Earp and his first wife, Abigail Storm. His mother died when he was two. Newton Earp, and half-brothers James and Virgil, were close for their entire lives. He married Jennie (last name unknown) in 1854. She died before 1887. He ran against his younger half-brother Wyatt for the office of constable. The Earps may have hoped to keep the job in the family one way or another. Wyatt won by 137 votes to Newton's 108, but their father Nicholas lost the election for justice of the peace in a very close four-way race.