PRIDE, ICON Sport, and SuperBrawl

In 2005, Noons won the PRIDE Fighting Championship's "Best Striker" auditions. Although, he never fought for the promotion, he fought for PRIDE's subleased promotion called SuperBrawl. Noons chose not to fight for PRIDE Fighting Championships because the promoters wanted to feature him in bouts against the top lightweights in the world, such as PRIDE's reigning Lightweight Champion, Takanori Gomi, and top contender, Joachim Hansen. Noons felt he was not ready to compete at the highest level that early in his career and chose a more conservative route. After three combined wins under the ICON Sport and SuperBrawl banner, Noons would move on to compete in bigger promotions.^[5]

Elite Xtreme Combat

In 2006, Noons signed a deal with promoter Gary Shaw that allowed him to participate in both boxing and mixed martial arts. Soon after, Noons was set to face former PRIDE veteran Charles Bennett in EliteXC's inaugural event in February 2007. Bennett won the bout via KO three minutes and forty-three seconds into round one, giving Noons only the second loss of his professional mixed martial arts career.

Noons rebounded from his loss to Bennett with a KO win over James Edson Berto at EliteXC's first ShoXC event. He then faced Nick Diaz for the promotion's first ever lightweight championship at EliteXC: Renegade. Noons dominated the fight using his outstanding boxing and striking against the Brazilian jiu-jitsu expert. Diaz attempted to take the fight to the ground but was unsuccessful with his takedown attempts and was also countered with a knee strike to the face on one occasion. Midway through the first round, Diaz was finally successful with a take down, but Noons got back to his feet instantly. Moments later, the referee would halt the fight and send Diaz to his corner to check on his cuts over his right eye. Diaz was given the o.k. and continued to fight. Noons would keep the fight standing and dropped Diaz with a straight right punch around the 2:07 mark of the round. After round one ended, the doctors in Diaz's corner stopped the fight due to how badly his face was cut. Noons was then declared the winner of the fight by way of TKO due to cuts, and would become the new EliteXC Lightweight Champion.

On June 14, 2008, Noons was successful in his first and only title defense with a TKO win over Yves Edwards in Hawaii at EliteXC: Return of the King.^[6] Following the fight, Nick Diaz, who fought on the event's co-main event, stepped into the cage to confront Noons for a rematch during K.J.'s post-fight interview with Bill Goldberg. After Noons asked the fans if Diaz deserved the rematch, Diaz grabbed a hold of Goldberg's microphone and said "Don't be scared homie", which resulted in an in-cage brawl.^[7] About two months later, Noons would be stripped of the title for refusing to rematch with Diaz.^[8] The promotion would then go defunct before a new champion could be crowned.

Strikeforce and DREAM

On December 2, 2009, Noons signed with mixed martial arts promotion, Strikeforce.^[9] While Noons was still competing in professional kickboxing as a teenager, he previously fought for Strikeforce on their kickboxing fight cards before Strikeforce became a mixed martial arts promotion in 2006.^[10]

In March 2010, Noons made his Japanese debut as he represented Strikeforce at DREAM 13. In his first MMA fight in nearly two years, Noons defeated Andre Amade via unanimous decision. Noons was the aggressor for the duration of the fight, and was visibly frustrated with Amade's uncharacteristically tentative fighting style throughout the fight, which seemed to be based on a counter punching technique.

Noons was set to make his Strikeforce debut against undefeated prospect Billy Evangelista at Strikeforce: Miami, but the fight was withdrawn after Evangelista suffered an undisclosed injury during training.^[11]

Noons would then be scheduled to compete in a rematch against Charles Bennett at Strikeforce: Fedor vs. Werdum.^[12] After Bennett pulled out of the fight due to scheduling conflicts, Noons was rescheduled to face Conor Heun at Strikeforce: Los Angeles in a catchweight bout of 160 pounds, which would take place ten days before the date he was originally set to rematch Bennett.^[13] Noons would go on to win a closely contested fight by split decision.

Noons next faced Jorge Gurgel on August 21, 2010, at Strikeforce: Houston. At the weigh-ins, the day before the bout with Gurgel, Noons weighed in at 156.25 pounds, a quarter of a pound over the maximum weight limit. Gurgel accepted the fight and waived off the extra weight, so the fight was continued as a lightweight bout.^[14] As the final seconds of the first round were coming to an end, Gurgel threw a flurry of punches while Noons responded with a left hook that landed and dropped Gurgel just a split second after the bell sounded at the end of the round. The crowd reacted to what appeared to be a late punch while a wobbled Gurgel was struggling to find his corner. Right at the opening bell for round two, Noons landed a right hand followed by a left hook that dropped Gurgel to the canvas once again. Noons looked to the referee expecting a stoppage and received no response. As Noons then continued to land punches on Gurgel, he threw a knee that appeared to land to the head of a still downed opponent, finally prompting the referee to stop the fight. Replay showed that the knee Noons threw did not land, although Noons's foot tapped Gurgel on the chin as it followed through. Noons was declared the winner by TKO at 0:19 of round two.

Noons moved up one weight class to fight Nick Diaz in a grudge rematch for the Strikeforce Welterweight Championship on October 9, 2010. Noons and Diaz previously fought at EliteXC: Renegade where Noons won by TKO due to cuts.^[15] Noons lost by unanimous decision (48–47, 49–47, 49–46), giving Noons his third career loss and first loss by decision, and beginning a losing streak for years to come. After the fight Noons revealed that he had sustained a broken jaw in the first round and a broken hand in the second.^[16]

Noons faced Jorge Masvidal at Strikeforce: Overeem vs. Werdum.^[17] Noons-Masvidal was set as a lightweight title eliminator, which would grant the winner of the bout a title shot against reigning Strikeforce Lightweight Champion, Gilbert Melendez. Originally headlining the preliminary card on HDNet, the bout was promoted to the Showtime portion of the main card after women's MMA superstar, Gina Carano, was pulled from the card. Noons went on to lose a unanimous decision.^[18]

Noons then faced Billy Evangelista at Strikeforce: Melendez vs. Masvidal in December 2011.^[19] He won the fight via unanimous decision.

Noons next faced Josh Thomson in the co-main event at Strikeforce: Tate vs. Rousey in March 2012.^[20] He lost the fight via unanimous decision.

Noons returned to face Ryan Couture at the final Strikeforce event, Strikeforce: Marquardt vs. Saffiedine, on January 12, 2013. Noons lost the fight via highly controversial split decision. All but one media outlet scored the fight for Noons,^[21] with a majority giving him every round. Couture admitted to being surprised by the verdict.^[22] Despite the loss, Noons still moved over to the UFC.

Ultimate Fighting Championship

In January 2013, the Strikeforce organization was closed by its parent company Zuffa. A list of fighters scheduled to be brought over to the Ultimate Fighting Championship was released in mid-January and Noons was one of the fighters listed.^[23]

In his UFC debut, Noons faced Donald Cerrone on May 25, 2013, at UFC 160.^[24] He lost the fight via unanimous decision.

In his second UFC fight, Noons faced George Sotiropoulos on October 19, 2013, at UFC 166.^[25] He won via unanimous decision, earning his first win under the UFC banner.

Noons faced Sam Stout in a welterweight bout on April 16, 2014, at The Ultimate Fighter Nations Finale.^[26][27] Noons won the fight via knockout in the first round, earning him his first Performance of the Night bonus award.^[28]

Noons next faced Daron Cruickshank on December 12, 2014, at The Ultimate Fighter 20 Finale.^[29] After a back-and-forth first round, the fight was stopped in the second round when Cruickshank received a second inadvertent eye poke from Noons and was unable to continue. Because they had not reached the third round, the fight was declared a No Contest.^[30]

Noons was expected to face Yan Cabral at UFC Fight Night 67.^[31] However, Cabral was forced out of the bout after contracting Dengue Fever and replaced by Alex Oliveira.^[32] Noons lost the fight via submission in the first round.^[33]

Noons faced Josh Burkman on February 6, 2016, at UFC Fight Night 82.^[34] He lost the fight by unanimous decision.^[35]

Noons was released by the company on April 14, 2016.

Mixed martial arts

• Ultimate Fighting Championship
  • Performance of the Night (One time) vs. Sam Stout
• Strikeforce
  • 2010 Fight of the Year vs. Nick Diaz on October 9
• Elite Xtreme Combat
  • EliteXC Lightweight Championship (One time, first, last)
    • One successful title defense
• PRIDE Fighting Championships
  • 2005 U.S. Auditions Winner
• Renegades Extreme Fighting
  • REF 2002 Lightweight Tournament Runner-up

Sanshou

• Art of War-K. Superstar Production
  • Art of War Sanshou Middleweight Championship (One time)
• U.S. Open International Martial Arts Championships
  • U.S. Open Sanshou International Middleweight Championship (One time)
• International Sport Karate Association
  • ISKA Amateur Sanshou International Super Middleweight Championship (One time)

Karate

• Long Beach International Karate Championships
  • 1997 17 and Under Kenpō Black Belt Gold Medalist