Diane was the first woman to serve as a law clerk to the Montana Supreme Court and the first woman appointed to the Montana Supreme Court. Barz is a graduate of Whitworth College and the University of Montana Law School. She has been a deputy county attorney and public defender. She and Doris Poppler established the first all-woman law firm in the Northwest in 1973. She was elected district judge in contested elections six times in an area covering five counties beginning in 1978. When her former law partner was appoiinted U.S. Attorney, she became an assistant U.S. Attorney for three years. She served ten years on the Montana Judicial Nomination Commission and participated in professional and community boards too numerous to mention. Diane was awarded the Distinguished Aluumni Award by the University of Montana in 2004. She is married to Dan Barz and they have one son and one grandson.