Conor is a record-setting hammer thrower. He began training at a young age with his father, Conor McCullough Sr., who competed in the hammer throw for Ireland in both the 1984 and 1988 Olympic Games. By the time Conor graduated from Chaminade, he held five national records and had won a silver medal at the 2008 World Junior Championships in Bydgoszcz, Poland.
Conor continued his athletic career first at Princeton University from 2010-2012, where he broke the 23-year old Ivy League hammer record in his first meet. In 2010, he not only claimed the national title at the USATF Junior National competition, but also secured his first international gold medal at the World Junior Championships in Moncton, Canada. In 2012, he was named the U.S. Track & Field and Cross Country Coaches Association East Region Indoor Athlete of the Year.
After the 2012 Olympic Trials, Conor took advantage of his dual-citizenship to begin competing for Ireland’s Crusaders AC in Dublin. He won the hammer title at the Irish Track and Field Championships in both 2011 and 2012, and set the Irish under 23 hammer record with a throw of 75.09 meters in Lucerne, Switzerland, in July 2012.
In 2014, Conor transferred to the University of Southern California where he majored in history. He placed second at the 2015 NCAA Indoor Championships and won the 2015 NCAA Outdoor Championship in the hammer throw. His winning of 76.91m throw was the longest throw by a collegiate athlete since May 2002. Conor made his Team USA debut as a professional in 2015. He finished second at the USATF National Championship and earned a bronze medal in the hammer throw at the 2015 Pan-American Games.
In 2016, Conor represented Team USA in the Men’s Hammer Throw at the 2016 Olympic Games in Rio di Janiero, Brazil. He finished 16th overall with a throw of 72.88m. He competed against 31 other Olympians, and was the highest ranking Team USA athlete for this event.