Boxing and MMA are usually considered close cousins in terms of combat sports. Despite this, crossover athletes between the two sports have been few and far between over the years. We’ve seen a number of MMA fighters enter the world of boxing, but boxers moving into MMA have been far less common.
We have seen a handful of big-time boxers enter the world of MMA, though, whether that’s been with the UFC or with lesser promotions. And interestingly enough, those boxers have struggled to find any success in the sport.
Here are five famous boxers who tried their hand at MMA and were unsuccessful.
#1 James Toney (UFC, 2010)
Probably the most infamous example of a boxer entering the world of MMA is James Lights Out Toney.
Widely recognized as one of the best boxers of his generation, Toney won world titles in three different weight classes across his near three-decade career.
His accomplishments included winning the IBF Middleweight Title, the IBF Super-Middleweight title, and the IBF Cruiserweight title.
1991 and 2003 saw him voted Fighter of the Year by the famed Ring magazine. And he even won the WBA Heavyweight title in 2005 before seeing the result overturned due to testing positive for steroids.
However, by 2010, Toney was years past his prime, and so he decided to switch sports and enter the world of MMA. Surprisingly enough, the UFC inked him to a big-money deal and matched him with legendary former UFC Heavyweight champion Randy Couture in his debut.
Toney talked a good game, claiming none of the UFC’s stars, including Couture, would be able to deal with his hand speed and punching power.
However, in the Octagon, it didn’t quite work out that way. Couture didn’t bother standing with Toney. He simply took him down using an ankle pick, and just after three minutes, slapped on an arm-triangle choke.
Toney was so panicked that he couldn’t even tap out correctly, instead waving his arms wildly in submission.
Weeks later, Toney was released from his UFC deal and headed back to boxing. He’d been taught an important lesson about how different the two sports were and still are.
#2 Muhammad Ali (1976)
Widely recognized as The Greatest, legendary boxer Muhammad Ali obviously competed years before the UFC or the sport of MMA were conceived.
However, it could be argued that he competed in one of the earliest forms of MMA fight. In June 1976, Ali faced off with Japanese pro-wrestling superstar Antonio Inoki in a mixed-rules fight labeled ‘The War of the Worlds.’
Ali was the reigning WBC and WBA Heavyweight champion at the time and was coming off a knockout win over challenger Richard Dunn just a month before to heading to Japan.
The fight took place under special, modified rules, largely due to demands and negotiations between the camps of the two fighters.
Eventually, it was decided that Inoki could not throw or tackle Ali to the ground and could only use kicks if he had one knee on the mat. That seemed to favor Ali, but the fight didn’t exactly play out that way.
Ali was restricted to landing just two jabs, while Inoki used a series of kicks – mainly from the ‘crab’ position on the ground – to break down the boxer’s legs. The fight eventually went the 15-round distance and was eventually declared a split draw.
While the fight was not well-received at the time – both by the crowd in attendance and viewers who watched on-screen – it certainly had some impact. Reportedly, the fight was the inspiration for the formation of the Pancrase promotion – one of the world’s first true MMA organizations.
#3 Ricardo Mayorga (MMA, 2013)
One of the most popular men in boxing during the early 2000s, Nicaraguan native Ricardo Mayorga gained a reputation as one of the sport's craziest men.
In his prime, Mayorga won the WBA and WBC Welterweight titles, as well as the WBC Super-Welterweight title.
He fought the likes of Vernon Forrest, Felix Trinidad, Oscar De La Hoya, and Shane Mosley during his career. Mayorga eventually stepped away from the sport after a 2011 loss to Miguel Cotto.
However, rather than simply retire, El Loco instead moved into the sport of MMA. He’d actually attempted the move in 2010 and was signed to fight UFC veteran Din Thomas for the Shine Fights organization. However, boxing promoter Don King put a halt to the move.
Eventually, Mayorga made his MMA debut on the regional circuit in May 2013. He was originally declared the winner in his debut after opponent Wesley Tiffer was unable to answer the bell for the third round.
However, the result was eventually overturned to a No Contest when it was decided that Mayorga had injured his opponent with an illegal knee to the spine – showing his lack of understanding in the sport.
El Loco went onto three more MMA bouts, all on the regional circuit. All ended in losses, with two of them seeing the boxer forced to tap out.
That was enough to put Mayorga off for good, and he moved back into boxing in 2014, never coming close to making the big time of the UFC.
#4 Ray Mercer (MMA, 2009)
1988 Olympic gold medallist and former WBO Heavyweight champion Ray Mercer actually won one of his two MMA bouts. However, the win's bizarre nature and the fact that Merciless never set foot into a cage again still qualifies him for this list.
In the late 1980s and early 1990s, Mercer was widely recognized as one of the world’s best Heavyweights. Renowned for his punching power, his fights with the likes of Tommy Morrison, Evander Holyfield, and Lennox Lewis went down as some of the most exciting of their time.
But after failing to win the WBO Heavyweight title in a fight with Wladimir Klitschko in 2003, Mercer decided to change things up.
He initially moved into kickboxing with Japan’s K-1 promotion. But he looked out of his depth in fights with Musashi and Remy Bonjasky and quickly stepped away.
This time, Merciless headed into the world of MMA. In a strange move, his first MMA fight came in 2007 against fellow debutant – street-fighting legend Kimbo Slice.
Fighting under the Cage Fury banner, the bout being considered an exhibition. Mercer was unable to use his boxing skills at all and found himself submitted by a guillotine choke in around a minute.
Two years later, though, Mercer was back. This time he signed to fight former UFC Heavyweight champion Tim Sylvia for the Adrenaline MMA promotion. And after a lot of negotiating, it was decided that the bout would take place with full MMA rules.
Sylvia clearly didn’t come into the fight taking it seriously, as he tipped the scales at well over 300lbs. And it cost The Maine-iac dearly, as Mercer caught him with a sledgehammer right hand after just nine seconds, knocking him silly.
It would be the last MMA fight for Mercer, as he claimed that MMA’s Heavyweights were afraid to fight him – despite the fact that Slice had submitted him.
And although 2010 saw him sign with the King of the Cage promotion, he never actually fought for them.
#5 Art Jimmerson (UFC, 1993)
The UFC’s first professional boxer, Art Jimmerson, didn’t win any titles inside the squared circle. However, he did put together an impressive record of 29-5 before his foray into MMA.
Instead, he was invited to the inaugural UFC event in November 1993, with the idea being that the promoters of the event wanted a high-level pro-boxer involved.
In reality, Jimmerson was brought to the UFC in order for the Gracie family to show the superiority of Gracie Jiu-Jitsu over boxing when it came to a “real fight."
Although the inaugural UFC tournament’s brackets were supposed to be randomized, a fight between Gracie and Jimmerson was set up for the tournament's first round. And after realizing quite what he was up against, Jimmerson made a decision that would turn him into a UFC legend.
He decided to wear just one boxing glove inside the Octagon – with the idea being that he could jab with the gloved hand while using his free hand to grapple. Unfortunately for him, it didn’t quite work out that way.
Gracie used front kicks to set up a quick takedown on the boxer and then advanced into full mount soon after. With Jimmerson looking lost on the ground, Gracie didn’t even need to lock on a submission before the boxer tapped out.
Unsurprisingly, no other professional boxers followed Jimmerson into the Octagon in the UFC’s early days, leaving his name to go down in history.
Jimmerson headed back into the world of boxing after his UFC experience – and now coaches stand-up at a UFC gym in Torrance, California.