On March 31, 2019, Tonon continued his consistent winning streak and fought Anthony Engelen at ONE Championship: A New Era. Tonon won via TKO in the first round. In May, Tonon faced Yoshiki Nakahara at ONE Championship: Enter the Dragon He won the fight via a heel hook submission in the first round.

As of August 2019, Tonon maintains a 5-fight win streak and is undefeated in mixed martial arts competition.

While he still maintains a consistent jiu-jitsu training schedule, since his debut in early 2018 Tonon has focused primarily on training and competing in professional mixed martial arts competition. He is an active fighter for the Singapore-based mixed martial arts promotion ONE Championship. He officially signed with the organization in October 2017.

In March 2018, Tonon made his professional mixed martial arts debut against Richard Corminal at ONE Championship: Iron Will, in Bangkok, Thailand. Tonon won the fight via TKO in the second round. Tonon had his second professional fight against Rahul Raju at ONE Championship: Reign of Kings on July 27, 2018. Tonon won the fight via rear naked choke in the third round. In November 2018, Tonon went on to fight Sung Jong Lee at ONE Championship: Heart of the Lion. Tonon won via guillotine choke in the second round.

From 2013 to 2017, Tonon went on to compete in numerous jiu-jitsu competitions as a black belt, including the IBJJF World & Pan American Championships, Eddie Bravo Invitational, Metamoris, Grappler’s Quest, North American Grappling Association (NAGA), Kasai Grappling, Polaris Pro Grappling, ADCC Submission Wrestling World Championship, and others. His most notable wins include matches against AJ Agazarm, Joao Miyao, Dillon Danis, Ralek Gracie, and Vinny Magalhaes.

As a child, Tonon was identified as having ADHD by his mother, an employee of a non-profit organization for children with special needs. Tonon had his first introduction to grappling when he joined the wrestling team at his school in 5th grade. Tonon continued to wrestle for several more years, through his freshman year of high school. Tonon has credited wrestling & martial arts with helping him to cope with his ADHD, and partially attributes his particular style of grappling to the disorder. He attended Lacey Township High School in Lacey Township, New Jersey, where he later graduated in 2009.

In 2008, after about a year of consistent jiu-jitsu training with DeBlass and Almeida, Tonon won his first title at the IBJJF World Championships in the Blue Belt Juvenile Division. After graduating high school in 2009, Tonon began pursuing a degree in exercise science at Rutgers University. While studying at Rutgers, Tonon maintained a rigorous training schedule and continued to compete in both local and international competitions, mostly competing in the gi for the first 5 years of his training, but later beginning to seek out more specialized, no-gi instruction from John Danaher. He was awarded his black belt by Tom DeBlass and Ricardo Almeida in September 2013. One month later, Tonon went on to compete for the first time in the ADCC Submission Wrestling World Championship in Beijing, China, where he had matches with Kron Gracie, Marcus Almeida, Roberto ‘Cyborg’ Abreu, and other well-known jiu-jitsu competitors.

Garry Lee Tonon (born September 12, 1991) is an American Brazilian Jiu-Jitsu practitioner and mixed martial artist. He is a five-time Eddie Bravo Invitational champion and has won titles at both the IBJJF World and Pan American Championships. He is a black belt in Brazilian Jiu-Jitsu under Tom DeBlass & Ricardo Almeida, and is the head instructor of Brunswick BJJ in South Brunswick, New Jersey. He has also trained extensively with Brazilian Jiu-Jitsu and mixed martial arts coach John Danaher at Renzo Gracie Academy in Manhattan.