Mark concentrates his practice in commercial and civil litigation. He has extensively defended product liability, professional and construction liability, trucking, and agriculture liability cases. He is chair of the firm's Construction Practice.

Mark has handled cases in state courts in more than 19 counties in northern Illinois, including Cook County, and in federal court in the Northern District of Illinois. He has successfully tried numerous high-exposure construction, trucking, and product liability cases to verdict. In October 2012, Mark obtained a defense verdict for a trucking company in a wrongful death lawsuit in LaSalle County, IL where the plaintiff claimed violations of numerous federal and state trucking regulations.