Garry Tonon was born and raised in New Jersey, coming of age in a small Jersey Shore community that formed the backdrop of his early athletic development. His mother, a recreation specialist at a non-profit organization serving children with special needs, recognized early signs of ADHD in Tonon and understood the value of structured physical activity in helping him manage those challenges. Martial arts proved transformative — channeling his energy and focus in ways that served him well into his professional career.

Tonon's grappling journey began in fifth grade when he took up wrestling, competing at the scholastic level for five years. That foundation instilled a competitive instinct and a pragmatic understanding of body control that would later define his submission grappling style. At age 14, his focus shifted to Brazilian Jiu-Jitsu, and he began training at various academies before finding his foundational home under Tom DeBlass at Ocean County BJJ in New Jersey — a partnership that would prove central to everything that followed.

Tonon's early competitive results signaled an exceptional talent. At age 16, in 2008, he captured his first IBJJF World title in the juvenile blue belt division — a result that announced his potential to the broader jiu-jitsu community. Competing in the IBJJF's no-gi circuit over the following years, he added No-Gi Pan American Championship gold at purple belt (2010) and brown belt (2011 and 2012), along with a No-Gi World Championship title at brown belt, building a decorated colored belt résumé that few could match.

It was at purple belt that Tonon earned the nickname that would come to define his competitive identity. In a July 2015 interview with Jiu-Jitsu Style (Issue 25), he described habitually taking opponents' backs and finishing with the rear-naked choke — known in Portuguese as the Mata Leão, or "lion killer" — and that is how "The Lion Killer" stuck. The name captured something essential about his predatory, back-taking style, which remained consistent across every level of competition.

On September 14, 2013 — two days after his birthday — Tom DeBlass promoted Tonon to black belt. His traditional lineage traces through DeBlass to Ricardo Almeida to Renzo Gracie, though Tonon described that environment as notably open to innovation rather than rigidly hierarchical. In the same 2015 interview, he recalled showing Renzo Gracie an unconventional single-leg variation as a blue belt, only to have Renzo ask to learn it — an anecdote that illustrated the mutual curiosity and collaborative spirit defining his team at every level.

Following his black belt promotion, Tonon quickly established himself as one of the premier no-gi and submission-only competitors of his generation. The Eddie Bravo Invitational served as an early showcase: he won the EBI Welterweight Invitational at both EBI 1 and EBI 2 in 2014, then added the EBI Lightweight Invitational title in 2015 and the EBI Light Heavyweight Invitational title in 2016 — demonstrating a rare ability to compete and win across multiple weight classes in the submission-only format.

At Polaris 1, Tonon faced leg-lock specialist Marcin Held and defeated him by leg lock — a deliberate statement that he had invested the technical work necessary to beat a specialist at his own game. The result reflected a broader training philosophy in which Tonon actively identified areas of potential vulnerability and addressed them through sustained, intentional practice.

At Metamoris 5, his match against Zak Maxwell showcased the positional complexity that made him so difficult to contain. In the July 2015 Jiu-Jitsu Style interview, Tonon described the sequence in detail: he escaped mount, worked from 50/50, turned his back to manufacture a transitional opportunity, swept from deep half guard, then converted a guard-pass attempt into an inside heel hook for the finish. The sequence demonstrated not only technical range but the composure to navigate multiple positional transitions under pressure before securing the submission.

Also in 2015, Tonon defeated Javier Vazquez by Triangle Choke at Gracie Nationals, and had previously submitted Lex Fridman in a submission grappling match in 2012.

At ADCC, Tonon became a fan favorite from 2015 onward for his aggressive, submission-hunting approach. His 2013 ADCC appearance in China produced one of the most discussed matches of his career: against Kron Gracie, he escaped deep attacks, built a points lead, and appeared on course for a defining victory before being finished by Rear Naked Choke in the final seconds following a center reset. In the 2015 interview, Tonon reflected that he had become distracted by the narrative of "beating Kron Gracie" rather than focusing on finishing the match. He accepted full responsibility, reported two sleepless nights afterward, then returned immediately to training — treating the loss as a technical and mental lesson rather than a reason to disengage. By 2019, he returned to ADCC and earned a third-place finish.

Tactical Foundation

Tonon's wrestling background forms the architectural base of his grappling approach. His stand-up game prioritizes establishing body-to-body contact — either by initiating takedowns directly or by permitting entries and countering to create dominant positions and transitions. This willingness to engage on an opponent's terms, grounded in confidence in his ability to counter, reflects a competitive philosophy built on preparedness rather than avoidance.

In the July 2015 Jiu-Jitsu Style interview, Tonon described his style as modern and unorthodox, blending fundamentals with evolving trends in jiu-jitsu and submission wrestling. He spoke of deliberately placing himself in bad positions during training to develop superior escapes and composure under threat — a methodology he credited directly for his ability to survive and counter in high-stakes situations. The Metamoris 5 and ADCC 2013 sequences both reflect this approach in practice.

Mental Framework

Tonon articulated a stark competition philosophy in that same interview, comparing his resolve to the Spartans at Thermopylae: either get his hand raised or go out on his shield. He framed it as a "kill or be killed" mentality — a refusal to compete for survival that manifested in constant forward pressure and submission hunting regardless of the score. He credited Tom DeBlass with building the mental fortitude underpinning this approach, citing DeBlass's mantra — "don't talk about it, be about it" — as a guiding principle.

Tonon also reflected candidly on two formative losses. Regarding a defeat to JT Torres at an Abu Dhabi Trials event, he attributed part of the result to personal distractions — staying up late arguing with his then-girlfriend — and cited fewer quality submission attempts than he expected of himself. He used the image of Torres' hand being raised as motivational fuel for roughly six months and ultimately ended that relationship, which he felt was impeding his professional growth. Regarding the ADCC 2013 loss to Kron Gracie, he was equally direct: fixating on the narrative rather than executing the task cost him the match.

Views on Competition Formats

On the question of competitive formats, Tonon argued in the 2015 interview that submission-only rules produce more aggressive, submission-focused matches with stronger spectator appeal. He expressed a preference for professional events with meaningful prize money — citing ADCC, Metamoris, and Polaris as aligned with his priorities as both a competitor and an academy owner — while acknowledging the prestige and marketing value of IBJJF points tournaments. He anticipated that submission-only formats would expand the sport's audience well beyond existing practitioners.

Tonon's development as a black belt was shaped significantly by his work with John Danaher at the Renzo Gracie Academy in New York. As of July 2015, he split his training time between RGA-NYC — where Danaher structured his competition camps — and his own school, Brunswick BJJ in New Jersey. Alongside Eddie Cummings and others, Tonon was a core contributor to the intellectual and technical environment that became known as the Danaher Death Squad, one of the most influential grappling teams of its era. The squad's systematic approach to leg locks, back attacks, and submission chains reshaped the competitive no-gi landscape.

Following the Danaher Death Squad's 2021 dissolution, Tonon followed John Danaher to Austin and aligned with the newly formed New Wave Jiu-Jitsu, training alongside Gordon Ryan and a room full of elite competitors. He has remained one of Danaher's most prominent students, assisting in instruction during New Wave classes and camps. At the 2022 ADCC World Championship, Tonon was present mat-side coaching teammates, demonstrating his investment in the team's collective success even when not competing himself. His integration within New Wave has kept his no-gi grappling at the cutting edge of technical development, running parallel to and reinforcing his MMA career.

Building an Undefeated Record

In 2018, Tonon shifted his primary competitive focus to mixed martial arts, signing with ONE Championship and constructing an MMA record that showcased the effectiveness of elite submission grappling in a cage environment. He compiled an undefeated run before earning a title shot in 2022, challenging for the ONE Featherweight World Title. That fight ended abruptly when Thanh Le knocked Tonon out at 0:56 of Round 1 at ONE: Lights Out on March 11, 2022 — the first loss on his professional MMA record.

Response and Continued Development

Rather than diminishing his trajectory, the knockout loss galvanized Tonon's development. In January 2023, he returned to the ONE cage and submitted Johnny Nunez with a first-round Kimura, demonstrating that his submission game translated seamlessly back into competitive pressure. In July 2023, he delivered what many regard as one of the most technically impressive performances of his MMA career, defeating previously undefeated Dagestani wrestler Shamil Gasanov with a Kneebar in Round 2. Gasanov had been a highly touted prospect, and Tonon handing him his first professional defeat — via a leg lock applied against an elite wrestler — reinforced the argument that advanced submission grappling remains a decisive equalizer at the highest levels of MMA.

Tonon and Gasanov met again at ONE Fight Night 34 on August 1, 2025, with Gasanov earning a decision victory in the rematch. As of mid-2025, Tonon had also discussed a potential MMA matchup with Kade Ruotolo as Ruotolo began his own transition into mixed martial arts — a prospective bout that generated significant interest given both athletes' grappling pedigrees. Throughout his MMA career, Tonon's approach has remained fundamentally BJJ-centric: even as his striking has developed, he consistently prioritizes bringing fights to the ground and hunting submissions — a competitive identity inseparable from "The Lion Killer" nickname he earned on the grappling mats.

Despite his heavy investment in MMA, Tonon has been unambiguous that he has not retired from submission grappling. In a 2023 interview, he explained that he remains open to competing in grappling again, provided the matchup is sufficiently compelling and does not conflict with his MMA schedule. He set a clear threshold: any return would need to be "very important…very exciting" — a marquee superfight at ADCC or a title match on a major grappling platform. He also expressed interest in facing Tye Ruotolo and Renato Canuto, among others, signaling unfinished business with the elite no-gi generation, and mentioned a desire for rematches with the last two men to beat him in grappling.

In October 2025, Tonon addressed the professional grappling landscape on a podcast, offering perspective on competition structure and promotion strategy. He criticized the Craig Jones Invitational's initial scheduling decision to launch its inaugural event on the same weekend as ADCC, arguing that forcing athletes to choose between events split both the field and fan attention. He credited ADCC for providing meaningful prize money and prestige during years when competitive opportunities were scarce, while noting that compensation across the industry still has room to improve. Tonon expressed skepticism about broad exclusive athlete contracts in the grappling economy — pointing to ONE Championship's arrangement with the Ruotolo brothers as a limited exception — and advocated for multiple promotions to coexist with distinct rule sets and better-staggered event calendars.

In December 2025, Olympic judo champion Satoshi Ishii publicly conferred an informal judo black belt recognition on Tonon following a period of working through judo techniques together, announcing the acknowledgment on social media. Ishii noted that only the Kodokan and International Judo Federation issue official judo black belts, but his public recognition served as a meaningful statement about Tonon's cross-disciplinary grappling competence and the respect he commands across martial arts communities.

Tonon has built a multifaceted professional platform around his competitive identity. As of July 2015, he owned and operated Brunswick BJJ in New Jersey, teaching classes and managing the business while maintaining an active competition schedule. He maintained close consultation with Tom DeBlass and Ricardo Almeida throughout that period and described a strong regional support network that included his own students — experience that provided the organizational foundation for a broader business presence.

Over time, Tonon expanded his brand through merchandise — including Lion Killer rashguards and related apparel — affiliate programs, and seminars held worldwide. The resulting business infrastructure provides the financial stability to pursue high-level competitive goals across both MMA and submission grappling without compromising the quality or frequency of his athletic preparation. His personal brand occupies a distinct space: fierce and technically serious as a competitor, while remaining accessible and relatable as a public figure — a combination that has sustained and grown his audience across multiple competitive eras.