In 2014, Dershwitz won the US Men's Saber National Championship, becoming the youngest US senior men's saber championship holder. Dershwitz then won the 2015 Junior World Fencing Championships in saber, becoming the inaugural U.S. men's saber fencer to win a world title. He is a four-time Pan-American Championship title holder, and the 2015 Pan American Games champion in saber. Dershwitz competed in fencing at the 2016 Summer Olympics. He returned to Harvard University as a sophomore, winning individual saber in the 2017 NCAA Fencing Championship and as a junior in the 2018 NCAA Fencing Championship. He won a silver medal in saber at the 2018 World Fencing Championships.