In 1975 John M. Phillips was appointed the Assistant District Attorney in charge of the Salinas office.  He served as the Assistant District Attorney until he was appointed to the Monterey Superior Court Bench in 1984.  He served on the Monterey County Bench for 21 years before retiring in 2004.

He served as presiding Judge of the Monterey Superior Court in 1989, 1996, 1998-2000.  While on the Bench he created the Domestic Violence Court and was the first chairman of the Domestic Violence Council.  He also was responsible for the development of the Mental Health Court.  He devoted many years on the Bench to the Family Law Court and was responsible for many of its current innovative services.

In 2000 he, along with other concerned citizens, founded Rancho Cielo, a successful and innovative program for at risk youth.  Since his retirement in 2004, he has devoted most of his time to the continued development of Rancho Cielo, until he was elected to the Monterey County Board of Supervisors in 2014.