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New England MMA Legend Sean Gannon Passes Away

Updated: Sep 13, 2021

It's with a heavy heart that we announce that New England MMA pioneer, Sean Gannon, has passed away at the age of 51. The Boston native had a heart attack on Monday and fell into a coma, and passed away peacefully yesterday morning.

Many newer fans to the sport of MMA in the region probably aren't familiar with Gannon, but if there was a New England MMA hall of fame, Gannon would undoubtedly be a first ballot inductee. He was a pioneer in so many aspects of combat sports in our region, and it goes without saying that our community has lost an invaluable member.

Not only was Gannon a hero in his everyday life as a member of the Boston Police Department for 20 years, but he was also, without question, a legend and pioneer in the sport of MMA in our region. Someone who impacted people in so many more ways than just being an incredible fighter.

The Early Years

One of Gannon's early training partners, Mike Littlefield, posted an awesome tribute to the fallen fighter yesterday, and talked about Gannon's early days training and competing in New England. Gannon regularly traveled around to train with some of the best fighters in the region, but he got his start at Boston BJJ where he first met Littlefield. Soon thereafter "The Cannon" was traveling to Taunton to train at Littlefield's "freestyle fighting" gym, The Boneyard, with some of the best heavyweights competing in this new sport in the region.

Soon enough Gannon was looking to test his skills in the sport of MMA, and made his amateur debut in 2003. He fought the likes of Josh Diekman and Mike Dexter over the next few years as he transitioned from an amateur to a professional. After defeating Mike Dexter at Mass Destruction 17 in August of 2004, Gannon had the opportunity to fight Dan Severn, but the local commission would not sanction the fight due to the gap in experience between the two competitors, but many knew that if Gannon could stay off his back against Severn, that he'd pick him apart on the feet and would surely come out the victor.

After disappointingly losing out on the Severn opportunity, Gannon came across an open invitation to fight a man who was shaking up the internet, in an unsanctioned bare knuckle fight. This fight would change the trajectory of Gannon's career and life.

The Fight That Broke The Internet In 2004

I'll never forget watching the unsanctioned fight that Gannon had against Kimbo Slice at an undisclosed gym in Rhode Island. Kimbo had caught my attention as a college kid. I came across the phenomenon that was Kimbo back in 2003/2004. He was destroying other insanely big fighters in backyard brawls, and was doing it with emphatic style. This was before the days of The Ultimate Fighter and Mixed Martial Arts being considered a legitimate sport. I was awestruck at the raw power, savagery, and marketability that Kimbo brought to his fights. He seemed to be not only the scariest human being on the face of the earth, but someone that would never be beat in an unsanctioned street fight.

This all changed when I came across a viral video online before things actually went "viral" on the internet. It was Kimbo's newest bout, and it was against a Boston cop in an undisclosed location in New England. Kimbo was from Florida and was managed by "Icey" Mike Imber, who also was a producer of pornos in Miami. Imber had put out an open invitation for any fighter in the world to take on Kimbo in a bare knuckle boxing street fight for $10,000. After Kimbo had dismantled numerous previous opponents in the backyards of Miami, there weren't many takers to step up to the challenge. Enter New England's Sean Gannon.

The Boston police officer was a 6 time golden gloves boxing champion and was also a high-level judo and BJJ practitioner in the region. He breathed, slept, and ate martial arts, and he was willing to step up and take on one of the most feared men in the world in a fight with no refs and very few rules.

Kimbo and his crew flew up from Miami and made their way to a martial arts gym in Rhode Island in late 2004. Keep in mind, this was before cell phone cameras, viral video clips, and MMA being a "sport". When I turned on this video my mind immediately went to infamous combat movies that I had watched during my youth. Bloodsport, Fight Club, and Rocky all came rushing back as I watched Gannon step into the make-shift ring to take on the monstrous, and seemingly unbeatable, Kimbo Slice. it had all the makings of a Hollywood script, and the bout kept me on the edge of my seat from the second they started throwing down.

There was no glove tap or pre-flight pleasantries. Just Gannon putting in his mouthpiece and both guys knuckling up to throw down in front of 20 or so spectators from both camps. I didn't understand the importance of this fight on so many levels as I watched it the first time, but what I did know was that this was a spectacle unlike any that I've ever seen, and when I say spectacle, I mean that in a good way.

Both Kimbo and Gannon threw down in a bare knuckle affair over the course of 10 plus minutes with no breaks. Both guys had taken a beating, and Gannon was showing the worst of it on his face (see Boston Herald front page below), but Kimbo had never fought anyone with the level of training and cardio that Gannon possessed. It was a grinding affair that wasn't for the faint of heart, but it truly was the rawest fight that any combat sports fan would ever witness, and that statement still rings true today.

The shaky camcorder video and makeshift ring only enhanced the visual that I was witnessing. There was technique, but moreso there was violence, brutality, and immence heart being displayed. Gannon continuously worked the body throughout the grinding affair, slowly sapping Slice's will. At one point the Boston cop landed some knees to the dismay of "Team Kimbo" as they proclaimed them to be illegal in this battle. The thing is, the boys from Florida expected a boxing match with no kicks, but they never outlawed the use of knees in the battle.

Gannon had put Kimbo to the mat multiple times, but the Floridian made his way back to his feet until the fight was eventually ended and Kimbo was counted out. Sean "The Cannon" Gannon had defeated one of the most feared men on the planet in 2004, and he did it at his game. It was one of the most epic fights I've ever seen still to this day. You can watch the fight in its entirety below.

It didn't come out until years later, but Gannon and Kimbo had agreed to make this a charity event, and donated the winnings to St. Jude Children's Hospital. This act was a microcosm of how both of these men carried themselves inside and outside the fighting world.

Gannon took some serious damage in the fight, and some have said that he was never the same after the absolute brutal bout with Kimbo. He also came under some serious heat from the Boston PD, and made front page news in the Boston Herald once the video was put on the web for everyone to see.

Gannon on the cover of the Boston Herald 12/1/04

Breaking Into The UFC

The video of Gannon battling Kimbo Slice was truly a viral hit before we even knew what a viral video was. This was a time before Facebook. Before YouTube. Before there was an easy way to distribute content on the internet. Regardless of the times, the 10 minute video of Gannon slugging it out with Slice became hugely popular, as many people sought it out through forum pages. I came across it on a thread on the UnderGround on, and that video completely captured my interest, and was one of the biggest impacts on me getting into judging, and now developing this website and also managing fighters.

After the video made its waves through the online fight community like a hurricane, Dana White and the UFC saw an opportunity to leverage the fame that Gannon brought to the cage as the only man to ever beat Kimbo Slice in a bare knuckle unsanctioned fight. "The Cannon" was brought in to fight Brandon Lee Hinkle at UFC 55 at Mohegan Sun in the co-main event in 2005. I remember the fight and the lead up to it like it was yesterday. There was an incredible buzz about Gannon making the walk under the evolving sport's brightest lights, but the excitement was short-lived, as Gannon was pretty easily handled by Hinkle and lost via TKO at 4:14 of the 1st round. The experiment was over, and Dana White cut Gannon after the one fight with the UFC.

The Years After Fighting

Gannon never stepped back into the cage to compete in MMA after the loss to Hinkle, and there were some thought that the concussions that he received against Slice and Hinkle may have effected him at a deeper level.

The Boston PD was none-to thrilled to see one of their own on the front page of the Boston Herald competing in an underground unsanctioned bare knuckle fight, and displaying a mangled face for the masses to see. This put Gannon and the Boston PD on an adversarial path for many years to come. In 2006 Gannon was eventually taken off the street and assigned to desk duty, as the BPD made the assessment that the concussions that Gannon received made him unfit to properly make high-risk decisions patrolling streets.

Never one to back down, in 2012 Gannon sued the city of Boston for restricting him to desk duty after he received clearance from numerous different doctors to safely patrol the streets of his home town. After a lengthy court battle the state's Supreme Judicial Court ruled in Gannon's favor, and granted him a new trial to determine whether he was fit to be on patrol.

Gannon made headlines again when he brought evidence to the FBI that highlighted a corrupt cops actions decades earlier. This act of whistleblowing got Gannon suspended and eventually fired from the force, but it is important to note that his actions shined a light on a police officer who had done some seriously shady stuff throughout his career. This was the type of guy that Gannon was - someone who shined a light in dark places for the betterment of society.

The Legacy Of Sean "The Cannon" Gannon

Over the past 24 hours social media has been flooded with stories and tributes to the man that was Sean Gannon. After reading these posts you quickly form an opinion of who Sean Gannon was as a person. Gannon may have had a hulking, rough exterior, but more importantly, he was an incredibly intelligent man with a big heart that exuded loyalty, friendship, and passion for people near and far.

"The Cannon" may no longer be with us, but he's left an undeniable mark on combat sports throughout our region. A man who positively touched so many lives inside and outside the combat sports arena. Someone who will forever live in our memories, and who truly was a pioneer in combat sports in New England. If you weren't familiar with Gannon before this article, do yourself a favor and start digging through the internet to better understand what he accomplished and who he was as a man. RIP big guy.

I was able to catchup with a few of Gannon's close friends to get their thoughts on the man, the myth, the legend that was Sean "The Cannon" Gannon.

Kevin MacDonald

Long-time MMA Official

"Sean was one of the kindest and legit good men Ive met through this sport. He was not only a legitimate OG, but a pioneer and mentor to so many on the local scene."

David Ginsberg

MMA Trainer, Coach, Official

"I’ve known Sean for 25 years as friend, training partner, coach, and martial arts brother. He earned his purple belt and Brown belt from me and it was an honor to build him. He was just about to get his black belt before he passed. Today I posthumously Awarded Him his Black belt that he had more than earned.

The thing about Sean is if you watch his Kimbo fight or any of his other fights, you might think he’s just a big bruiser. But beyond Boxing, BJJ and MMMA championships, he was a deeply intelligent, caring, hilarious, analytical thinker and person, and quite intellectual. He was full of wisdom.

Regarding his fighting, it was the camaraderie and the team experience, the family and brotherhood experience that he thrived on. I do not believe he fought to be brutal or to rejoice in a decisive or violent victory. I think what did it for him was the connection and that he could inspire people. Which he did.

About 10 years ago I had a conversation with him, and it was deep and it was quiet and it was understated. He told me he considers himself a protector of the realm. A gladiator who protects the gates of the city. He considered that an age old role. And it was one of those moments when as the words were coming out and he was saying it, it just struck me how true it was.

For the first 10 years I knew him I was always just a little afraid of him. Back in the 90’s, he used to seek two guys out to roll with: myself and Kenny Florian. We were amongst a very small group of guys that could challenge him on the mat and catch him in submissions. I would hold pads for him and I learned very quickly how to hold pads because his power was tremendous. So for those first 10 years, I was always a little afraid and had this feeling like I had befriended a grizzly bear in the wild and yes he was nice and we liked to play fight, but I wasn’t sure that he wouldn’t just decide to suddenly go into wild grizzly hulk mode.

Even while being a great combat athlete and a great coach to many athletes, Sean was a gentle giant. It was my honor and privilege to be able to be his jiujitsu professor in the second part of our friendship, which lasted the last 10 or so years. Whenever he came to the gym, he would help someone get ready for a MMA fight and he was a wealth of knowledge and an encyclopedia of great hybrid techniques blending wrestling, boxing, muay thai, and judo.

His sense of humor was as legendary as his epic battle with Kimbo. Sean was always there for me or other folks, if there was ever a time of need. And even as an experienced fighter, martial artist, and coach, he still came in and was hungry to learn and asked me a lot of very specific nuanced questions about side mount maintenance, side mount escape, and a lot of my constricting style of BJJ. And then he would drill the crap out of it and incorporate it into his live grappling game. He was humble enough to ask to learn something and this was part of his wisdom, kindness, and giving. Sean, a big burly funny man was friendly to everyone in my gym, from all walks of life, without hesitation. At first people saw a big scary towering Hawking combat machine, then they realized who he was and were starstruck, but they always left their first meeting saying they couldn’t believe what a warm funny humble hilarious man he is."

Kirik Jenness

"We’ve all heard the Indian parable of the blind men and an elephant, wherein each man describes something different. Sean Gannon, a giant and an actual genius, was so large a figure that we each have our own unique, vivid, even profound experiences with the man. I knew Sean by ferocious reputation, but first met him properly when he fought for Mass Destruction in the early 2000s. He walked out to the Cops theme, in fight shorts and a ballistic vest, swinging a PR-24. Sean stopped his opponent with hook to the liver. He took some shots in the process, went back to the locker room, puked, showered, and went straight to work patrolling the streets of Boston on a Saturday night. My initial reaction was “what the f*** just happened?”

Over the years I got to know Sean better, and we worked together, at one point getting over 100,000 views for a piece we did, to this day the record for my site. That’s Sean - whatever it was, Gannon was better, badder, bigger, stronger...... and smarter. I cannot tell you I fully knew Sean Gannon. You see, I’m the blind guy, and he’s the true king of the jungle. I saw what I could see, but I lack the depth and breadth to see it all. Maybe that’s true for all of us. But, what I knew, I respected and loved."

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