O'Connor has competed in five Olympic Games, representing the US team at all five and also riding as an individual at three. At the 1988 Summer Olympics, riding The Optimist, she posted a DNF (did not finish) in both the team and individual portions. At the 1996 Summer Olympics, riding Biko, she and the US team rode to a silver medal. At the 2000 Summer Olympics, riding Prince Panache, O'Connor and the US team again took a medal, this time bronze. O'Connor did not ride as an individual at either the 1996 or the 2000 events. In the 2008 Summer Games, riding Mandiba, she placed 44th individually, while the US team took 7th. O'Connor was not originally scheduled to ride in the 2008 Games, but was moved to a competition spot in July 2008 when teammate Heidi White was forced to withdraw. Four years later, at the 2012 Summer Games, the US team repeated their placing, while O'Connor improved to 9th, riding Mr. Medicott. Her 9th-place finish was the highest rank achieved by a US equestrian at the 2012 Games. O'Connor was the oldest Olympian to represent the US in any sport at the 2012 Games.