Who became the first Olympic gold medalist to win a professional heavyweight world title?

Floyd Patterson became the first Olympic gold medalist to win a professional heavyweight world title. He achieved that milestone by stopping Archie Moore in the fifth round on November 30, 1956, in Chicago.

Patterson had won middleweight gold for the United States at the 1952 Helsinki Olympics. Although he was a relatively compact heavyweight, he developed into a leading professional contender under trainer Cus D'Amato. When Rocky Marciano retired in 1956, Patterson entered the process to determine the champion's successor.

His victory over Moore made Patterson the youngest heavyweight champion in history at the time: he was 21 years old. The achievement also connected amateur and professional boxing in a particularly notable way, because Olympic success did not automatically translate into a professional title in that era.

Patterson later lost the championship to Sweden's Ingemar Johansson in 1959, then regained it by knockout in their 1960 rematch. That made him the first boxer to reclaim the undisputed heavyweight championship, another landmark often associated with his career.