When he was 15 Ian Thorpe won the 400 meter freestyle at the world championships. This made him the youngest male swimming world champion ever.
The current youngest formula 1 champion is Sebastian Vettel
Brock Edward Lesnar three-time WWE Champion, is the youngest WWE Champion in history age 25.He Became the youngest WWE champion by defeating Dwayne "The Rock" Johnson at Summerslam 2002Randy Orton is the youngest world heavyweight champion age 24
The youngest lightweight boxing champion was Muhamid Ali. He was considered a lightweight player at 205 lbs at age 17 and he was champion.
The youngest WWE Intercontinental Champion was Jeff Hardy. He was 23 years, 222 days.
It is Mike Tyson when he was fighting with Trevor Berbick He became the youngest heavyweight champion in history.
Iron Mike Tyson was the youngest heavy weight champion ever at 20 years old.
Seve Ballesteros, 1980 and 1983 Champion.
Paige is the youngest WWE Divas Champion because she was only 21 when she won it against Aj Lee in her debut.