Career
He is the brother of Robert Marx, who has also represented the United States. in multiple Olympic fencing events. He is also a five-time Olympian in both foil and epee (1980,1984, 1988, 1992, and 1996). He served as vice president of the United States Fencing Association () from 1992 and 1996.
Marx received his Master of Arms degree in Poland in 1993 after spending several months studying under Professor
Zbigniew Czajkowski at the Academy of Physical Education in Katowice. In recent years he has served as the United States. national women"s épée coach, and his students have included United States. Team member Cody Mattern.
Marx was fencing master at Northwest Fencing Center in Beaverton, Oregon, until 2008 when he accepted a position as full-time assistant coach at Duke University in North Carolina. Marx returned to Northwest Fencing Center after a year as a coach at Duke University.
Since January 2010 he has been Director of Fencing Operations at the Boston Fencing Club.
In July 2014, Marx founded Marx Fencing Academy, located in Concord, Massachusetts.