Pride FC and Shooto Japan

Newton started his Japan fight career with a win over Erik Paulson to become the Vale Tudo Japan World Champion. After a few dominating fights in the Shooto organization, he then moved on to PRIDE FC, considered to be the top MMA show in the world along with the UFC. In June 1998, Newton lost a technical bout in Pride Fighting Championships against Kazushi Sakuraba. The Sakuraba vs. Newton fight is remembered today as a classic and one of the best MMA fights ever for submission grappling fans. This legendary fight propelled both fighters to MMA superstardom. Newton went on in the PRIDE Japan to rack up wins over Daijiro Matsui, Naoki Sano, Johil de Oliveira, all on his way to a spectacular armbar victory over "Pelé" José Landi-Jons at Pride 19 in February 2002. After this win Pride President Naoto Morishita declared, "Newton is considered the unofficial PRIDE middle weight Champion". In October 2003, Newton gained a split-decision victory over Renzo Gracie at Pride Bushido 1.

Ultimate Fighting Championships

Newton's fourth and fifth fights marked his UFC debut at UFC 17, defeating Bob Gilstrap and losing a controversial decision to Dan Henderson on the same night for the middle weight tournament title. Newton's greatest professional accomplishment in his career was capturing the UFC Welterweight Championship from Pat Miletich in May 2001 at UFC 31. The reign was short-lived however, as Newton lost his first title defense in November of that same year at UFC 34 against accomplished wrestler Matt Hughes. Newton had a triangle choke locked in on Hughes, but Hughes picked up Newton, walked him to the corner, and attempted to slam him. Newton placed his arm over the side of the cage to prevent the slam, causing John McCarthy to warn him, before Hughes seemed to lose consciousness and fall to the mat while still holding Newton, causing Newton to hit his head and also lose consciousness. With Hughes slow to get up and Newton out cold on the mat, McCarthy would award the victory to Hughes via KO. The ending of the fight proved to be controversial, as many believed that Hughes was unconscious before Newton, who should have been awarded the victory as a result.

K-1 HEROs

Newton was set for a comeback fight at K-1's HEROs MMA promotion against Melvin Manhoef at the Ariake Coliseum on August 5, but had to pull out of the fight at the last minute due to a torn ligament in his knee. He made a second attempt at a comeback in K-1 HEROs, this time facing Tokimitsu Ishizawa. Newton made short work of the Japanese fighter, needing only four punches to score the TKO victory in just 22 seconds. He then faced Shungo Oyama at Hero's Korea 2007 where he lost by submission due to punches.

International Fight League

Newton and Riggs were the coaches of the Toronto Dragons in the IFL in the 2005 and 2006 seasons. Based out of Warrior MMA in Newmarket, the Dragons were made up of international notable fighters such as Claude Patrick, Wagnney Fabiano, Brent Beauparlant, Rafael Cavalcante, Leo Santos and Dennis Hallman. The Dragons made the playoffs in the 2006 season and went on as far as the semifinals round. Wagnney Fabiano from the team qualified and won the IFL Lightweight Championship. Newton fought in a superfight that year and lost to Renzo Gracie by way of an extremely controversial split decision at the IFL Championship Final. Gracie himself questioned the call after the fight.

W-1

Carlos, motivated by a chance to compete in Canada, made a return to MMA again in 2009 at Warrior-1: Inception. He scored a first round victory by way of KO against Nabil Khatib, this was Carlos's first fight on Canadian soil in 13 years. He again returned to action on October 10, 2009, against former UFC veteran "Mr. International" Shonie Carter at Warrior-1: High Voltage. The bout was to be for the Warrior-1 Welterweight Championship, but because Newton did not make weight, it was a non-title bout. Newton beat Carter by unanimous decision after three rounds.

In 2009, after his win over Shonie Carter, he stated in an interview to Sherdog that he was anticipating his return to fighting abroad, with particular interest in Japan. However, after one more fight in Australia, Newton decided, that after a successful fight career that spanned 14 years, it was finally time to take a break and focus on coaching.

Following his retirement, Newton had coached at his home gym, Warrior Mixed Martial Arts, in Newmarket, Ontario, until he eventually opened and began coaching at his own gym, Newton Mixed Martial Arts, in Pickering, Ontario.^[1]