Marcus Berghahn defends individuals and businesses accused of criminal misconduct. His practice encompasses all types of criminal cases at all stages of criminal proceedings-investigation, pre-charging negotiation, practice before a Grand Jury or a John Doe magistrate, motion hearings, jury trial, sentencing-on through to appeal. Because of the depth of his experience, Marcus also counsels witnesses and victims when they are involved in criminal proceedings. Marcus takes pride in helping clients through a very difficult time in their lives and delivers on what he believes are three core client needs: "Helping clients understand exactly what will happen at each stage of their case and what that means for them; having compassion for the stress and anxiety attendant to criminal cases; and listening to a client’s concerns and priorities in order to deliver the best advice possible, leading to the best result possible."

Marcus lectures regularly on topics of criminal law at continuing legal education seminars. He is an adjunct professor at the University of Wisconsin Law School where he teaches a seminar on constitutional and criminal law. Marcus is a double Badger, completing both undergraduate and law school at the University of Wisconsin-Madison.