After playing football for seven years, in 1983 Peter Aerts started to practice Tae-Kwon-Do. His interest in fight sports came from his grandfather as well as an uncle who were active in that field. In 1984 he picked up kickboxing and started training in “Judoka-Kickboxing” in Best, Netherlands with Eddy Smulders. After a year Aerts fought his first match, and soon one victory succeeded the other. He won his first world championship title when he was nineteen.

Peter Aerts then switched to club “Champs” in Eindhoven, with Eddy Smulders, where he became world champion for the second time. After that he moved to the famous Chakuriki gym of Thom Harinck, where he had his greatest successes. In 1994 Peter Aerts became the K-1 World Champion for the first time, following up his success in 1995 and 1998. His win in 1998 was the fastest tournament win in K-1 history, when he knocked out all of his opponents in the very first round in a record time of 6:43 minutes, until August, 2009 where Daniel Ghita won the K-1 World Grand Prix 2009 in Tokyo Final 16 Qualifying GP in 5:15 minutes. In 2009 Semmy Schilt also surpassed Aerts fastest World Grand Prix win after winning the 2009 World Grand Prix Final in 5:54 minutes.

In 1997 He broke the work relationship wth Thom Harinck. He later moved to train with Andre Mannaart, a former K-1 fighter himself. In December 2, 2006 Peter Aerts entered the K-1 World Grand Prix 2006 as a reserve fighter, defeating his opponent Musashi vby first round knockout. After Remy Bonjasky was forced to withdraw from the tournament due to an injury, Aerts met Glaube Feitosa in the semifinals, winning his fight by TKO in the second round. His opponent in the finals was reigning World Champion Semmy Schilt, Aerts lost the fight by unanimous decision.

On September 29, 2007 Aerts met Ray Sefo at the K-1 World GP 2007 in Seoul Final 16 in Korea. He won the fight at the end of the first round by TKO corner stoppage when Ray Sefo did not answer the bell and qualified himself for 15th consecutive year to K-1 World GP 2007 Final held in December 8, 2007 at the Yokohama Arena, Japan. In quarterfinals, Aerts knocked out Junichi Sawayashiki from Japan in the first round. In the semi finals, he defeated two time K-1 World Grand Prix winner Remy Bonjasky by unanimous decision. He then moved on to face two time defending champion Semmy Schilt in the finals. Aerts lost the bout by TKO in the first round after suffering a knee injury.

Now he has organized a team of his own, Team Aerts.