1952 Helsinki Games, 1956 Melbourne Games, 1960 Rome Games, 1964 Tokyo Games
Track and field
Medal count: Two golds, one silver
A back-to-back gold medalist in 1952 and '56, O'Brien created a new method of throwing the shot, starting with his back to the field and twisting around to add momentum to his toss. This radical change in style led him to 17 shot put world records, including the first throw to break 60 feet. Despite winning 116 contests in a row prior to the 1960 games, he finished that event with a silver.