Mark is a retired active-duty United States Army Officer, having served for 20-plus years. He culminated his career as a member of what is now known as the Defense Clandestine Service. He is a two-time graduate of the Defense Language Institute and a life member of Veterans of Foreign Wars. His awards and decorations include the Legion of Merit and Parachutist Badge.

Mark has an associate’s degree from the University of Alaska, a bachelor’s degree from the University of the State of New York, a master’s degree in international relations from Troy University and a Juris Doctor from the Southern Illinois University School of Law.

Mark has tried to verdict a countless number of first-degree murder cases, including a number of multiple-victim homicides. He is a life member of the Illinois Association of Criminal Defense Lawyers, where he serves on the Board of Directors. He is a life member of the National Association of Criminal Defense Lawyers. He is the former chair of the Illinois Bar Association’s Standing Committee on Corrections and Sentencing. He is also the former Chair of the Illinois State Bar Association’s Criminal Justice Section, where he serves as the Editor of the Criminal Justice Newsletter.