After taking up weight lifting in his teens to fill out his slender build, Oerter was a football player and sprinter in high school. He discovered his discus ability when he idly picked up the discus and threw it farther than anyone else on the track team could. He attended the University of Kansas on a track scholarship (1954–58) and won six national Amateur Athletic Union titles.

Although his original goal was to win five gold medals, Oerter retired from Olympic competition after the 1968 Games with four because of the sacrifices and pressures of being an Olympic champion. He resumed training in 1976, however. While he narrowly failed to qualify for the U.S. Olympic team in 1980, which ultimately did not compete (there being a U.S. boycott), he made the longest throw of his career and the world's longest that year, 69.46 metres (227 feet 11 inches). Though active at a world-class level into his 40s, he fell short again in bids for the U.S. Olympic team in 1984 and 1988. He was a world record holder in Masters track-and-field competition in the 1980s. Oerter was in the first class to be inducted into the U.S. Olympic Hall of Fame in 1983.