Iwao Horiuchi competed in freestyle wrestling at the 1964 Tokyo Olympics, winning a bronze medal, and returned to the Olympics in 1968, with less success. He never lost an Olympic match in 1964, with four wins and a draw, but his 6 bad points eliminated him from gold medal contention. Horiuchi was a Japanese champion while he was a student at Nihon University. He was World Champion at 70 kg in 1963 and won a silver medal at the 1966 World Championships.
| Games | Discipline (Sport) / Event | NOC / Team | Pos | Medal | As | |
|---|---|---|---|---|---|---|
| 1964 Summer Olympics | Wrestling | Iwao Horiuchi | ||||
| Lightweight, Freestyle, Men (Olympic) | 3 | Bronze | ||||
| 1968 Summer Olympics | Wrestling | Iwao Horiuchi | ||||
| Lightweight, Freestyle, Men (Olympic) | 7 |