Ronn Couillard has worked in the California criminal justice system since 1968, beginning as a deputy district attorney for Los Angeles County. In 1980, he moved to Visalia and served as a deputy district attorney. He was appointed to the Tulare County Superior Court in 1987 and retired in 2007. He has prosecuted and presided over all types of felony matters, including numerous murder cases. He and his wife, Charlotte, reside in Visalia, California. They have four children and seven grandchildren.