Prior to private practice, Marc was a prosecutor for 14 years, investigating and trying complex cases involving multimillion-dollar bank frauds and government corruption. As a faculty member of the National District Attorneys Association and the New York Prosecutors Training Institute, he trained law enforcement personnel across the country on ways to successfully investigate and prosecute sophisticated bank and mortgage fraud. He served as Chief of the Suffolk County District Attorney’s Office Public Integrity Bureau before becoming Suffolk’s Deputy County Attorney. In that capacity, Marc handled state and federal matters including real property, employment, civil rights, class action, and negligence claims, as well as Article 78 proceedings. Marc clerked with the Hon. Barrington D. Parker, Jr., U.S. Court of Appeals, Second Circuit.

Marc has also been active in the U.S. Army, deploying to Iraq as a platoon leader in 2005-2006 and earning the rank of lieutenant colonel in the New York Army National Guard.