As a teenager Klaus Nonnemacher went to Jurgen Lutz’ Bulldog Gym to learn karate, ninjutsu and kickboxing. As other fighters from this gym he became a famous competitor, but unlike his team mates he wouldn’t settle for one sport alone. Klaus Nonnemacher fought it all. First he competed in point fighting and then in Dutch Kickboxing. On and off Klaus Nonnemacher fought fullcontact, too, where he battled against Canadian Jean-Yves Theriault and Polish sensation Jozef Warchol.
After becoming a world champion in Taekwondo he retired from competition and devoted his career to the commercial aspect of the sport. He managed the WKA, World Karate and Kickboxing Association over several years before deciding to found a start-up by creating the WKU, World Kickboxing Union. His WKU sanctions professional fight cards and organizes amateur kickboxing tournaments in Germany and various other countries including the USA.