János Mohos started his sports career as a fencer with Bp. Honvéd in 1948. His major achievement was when he won the national youth championship title in sabre. After the revolution, in December 1956, like so many Hungarian fencers, he fled to Switzerland, where he won 6 individual and 24 team championship titles in sabre, and in Swiss colors he competed at the München Olympics. After completing his active sports career, Mohos worked as a fencing master from 1973 and was also active as an international judge for decades. After retiring from competition, he moved back to Hungary, where he helped mentor the next generation of Hungarian fencers.