John DeSanto was born in Duluth and graduated valedictorian from Duluth Cathedral High School in 1964. He received a B.A. from the University of Minnesota Duluth in 1968 and went on to study law at the University of Minnesota, graduating in 1973. In 2009 DeSanto was appointed trial court judge for Minnesota's Sixth Judicial District after 35 as Assistant St. Louis County Attorney; he finally retired for good in 2015. DeSanto and his wife, Lana, live in Duluth and are the parents of three adult children, Amy, Abby, and Adam.