On March 26, 2005, Le Banner knocked Yoshihiro Akiyama out by knee kick in MMA rule at Hero's 1. On May 13, 2006, at K-1 World Grand Prix 2006 in Amsterdam, Le Banner fought against two-time K-1 world GP champion Remy Bonjasky. The fight was rather controversial as Bonjasky won the fight in a majority decision by all Dutch judges despite being dominated in this fight. On June 30, 2006, K-1 judges admitted the decision was a mistake, and this match's result was officially changed to "Le Banner defeated Bonjasky by unanimous decision (30–29)". In 2006, Le Banner announced that hope to fight against current UFC heavyweight world champion Tim Sylvia in UFC rule. On December 2, 2006, after his loss against Semmy Schilt at K-1 World Grand Prix 2006 finals, Le Banner announced he was considering his semi retirement from tournament fighting, restricting future appearances to K-1's Superfight events. In early 2007, after his fight at K-1 World GP 2007 in Yokohama he was forced to have knee surgery and was not expected to return to the ring until 2008; however due to a fast recovery K-1 announced that Le Banner would participate on September 29, 2007 at the K-1 World GP 2007 in Seoul Final 16 against Russian kickboxer Ruslan Karaev. Just two days before the fight, Karaev had to pull out and was replaced by a former Korean Taekwondo practitioner, Yong Soo Park. It took Le Banner only 0'54" seconds to knock out Park in the first round with a straight punch and qualify himself for the K-1 World GP 2007 Final held on December 8, 2007 held at the Yokohama Arena, Japan. On December 8, 2007, in the ninth K-1 World GP appearance of his career, Le Banner defeated Choi Hong Man in the quarter-finals by unanimous decision before facing the reigning K-1 champion Semmy Schilt in the semis. Le Banner finished the first round up on scorecards. In the beginning of the second round Schilt landed a low kick that seemed to hurt Le Banner's right knee, on which he had surgery in early 2007. The fight was eventually stopped by Le Banner's corner throwing the towel to avoid further damage to the injured knee. Jerome fought Schilt again at the K-1 World GP 2008 in Fukuoka for the K-1 Super-Heavyweight title. Jerome ended up losing a controversial majority decision.