Matthias Behr is married to the former foil fencer Zita Funkenhauser. After termination of his career as a competitive athlete, he became principal of the part-time boarding school at the Olympic base of Tauberbischofsheim.
During his career as a fencer, he was part of a group of foil fencers from Tauberbischofsheim, or from the competitive centre there, who dominated their field nationally and internationally for almost 15 years.
On July 19, 1982, in the middle of his career, Matthias Behr, and foil fencing in general, became widely known outside of those interested in the sport, due to a deadly accident at the world championship in Rome, when Behr's blade broke and fatally injured the most successful foil fencer of the time and incumbent world champion, Vladimir Smirnov, in the head.
Matthias Behr was one of the close confidants of Emil Beck, and became his successor as team leader of the National German Fencing Team.