Judge Marks was born and raised in Clarksburg. He attended Harrison County public schools and has a 1974 political science degree from West Virginia University and a 1977 law degree from West Virginia College of Law.
He practiced law in Clarksburg from 1977 to 1996, concentrating in the area of criminal and civil trials.
He was appointed by then-Governor Gaston Caperton to the bench in the Fifteenth Judicial Circuit (Harrison County), taking office on February 1, 1996. He was elected in 1996, 2000, and 2008. He has served as chief judge several times during his tenure on the bench.
He is a member of the West Virginia Judicial Association, the West Virginia State Bar, and the Harrison County Bar Association.
He received the 2000 Outstanding Judicial Service Award from the West Virginia Trial Lawyers Association. He has been assigned to sit on the Supreme Court of Appeals of West Virginia as a temporary justice