Scion of one of the most illustrious families in American fencing history, Dean Cetrulo began fencing at the age of 10, taking instruction from his father, Gerardo Cetrulo, an Italian fencing master and longtime coach at Dartmouth. A champion in high school, he attended Seton Hall University, where he was coached by his older brother, and won the Eastern Intercollegiates in foil and sabre in 1940 and 1941. In 1941, aged 22, he became the youngest national champion to that time by winning a four-way barrage for the foil individual title. He repeated as foil champion in 1947 and added the sabre individual title in 1948. Cetrulo, who represented the Salle Santelli, was a member of five national championship teams. At the 1948 Olympics, Cetrulo fenced two weapons, the only U.S. fencer to do so. Besides the bronze medal in team sabre, he was a member of the fourth place foil team, and made the semi-finals in sabre individual and foil individual; in the latter case, failing to make the final on a barrage. During World War II, Cetrulo was a first lieutenant in the U.S. Army air force, and was shot down over Italy. After being captured by the Germans and imprisoned in a POW camp, he made a successful escape. He was hidden by an Italian family in a small town north of Naples, until the Allies liberated that city and he could be repatriated.