How Muhammad Ali Stacks Up Against History's Greatest Heavyweights

Muhammad Ali's death has offered fight fans a chance to reflect on his greatness as a professional boxer. Self-proclaimed as “The Greatest,” there is no shortage of support for that assessment. Ali is the most popular and well-known fighter ever, and the passing of time since he retired from boxing in 1981 has done nothing to diminish his status as one of the best heavyweight champions of all time.

His death has only intensified the ongoing debate among fight fans and historians about who should be considered the best heavyweight boxer ever. Ali, who was the first heavyweight to ever win the lineal championship three times in a career, fought during perhaps the division’s greatest era and proved himself the best. He dazzled fans with wins over a multitude of heavyweight greats, including Sonny Liston, Joe Frazier and George Foreman.

But what about heavyweight champions from other time periods? How would Ali have fared against the all-time greats he didn’t get to fight? Would old-timers like Jack Johnson and Jack Dempsey rough him up? Could the massive super heavyweights like Lennox Lewis and Wladimir Klitschko use sheer size to overwhelm him?

Let's take a look at how Ali would have matched up against some of the best heavyweights ever.

Assumptions and Clarifications

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Imagining great fighters from one era fighting those from other eras is exactly that: imagination. While it’s fun to debate who would beat who, the truth is no one knows a darn thing.

For the purposes of this exercise, Ali, as well as his opponents, are at their peaks. Moreover, boxing rules have changed so drastically through the years that we must also choose which to go by. Fighters such as John L. Sullivan and James J. Jeffries were fighting in an almost entirely different sport.

For Ali’s bouts against these gentlemen and the rest, he will be fighting his competitors under the standard rules of his era. The fighters will use modern-day gloves, participate in same-day weigh-ins (which effectively means nothing for heavyweights) and the bouts will be scheduled for 15 rounds. 

Finally, great heavyweights such as Liston, Frazier, Foreman and Larry Holmes were excluded because Ali faced them during his career. While he may have only been at his best against Liston in the rematch and was a shell of himself against Holmes, we can reference those encounters to get a semblance of how those fights might go.

For transparency’s sake, I favor Ali over all of them, prime versus prime, except perhaps Frazier, who gave Ali the fight of his life every time they matched up. The two were meant for each other.

John L. Sullivan

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Analysis: John L. Sullivan was a rugged, tough fighter who was large in physical stature for his era. At 5’10” and around 200 pounds, Sullivan was shorter than Ali and weighed less, too. Footage of Sullivan is limited in quantity and terrible in quality, so it’s difficult to tell how good a fighter he was.

Christopher Klein, author of Strong Boy: The Life and Times of John L. Sullivan, wrote this for Biography.com in 2015:

Conclusion: The so-called Boston Strong Boy fought during an age when the mainstream of society considered boxing unacceptable. He was a barrel-chested ruffian, but he never saw the likes of Ali during his travels. Sullivan would do his best, but Ali would crack him hard as he strode forward into the fire to show everyone how tough he is. That’s the wrong move. 

Verdict: Ali via Round 3 KO

James J. Jeffries

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Analysis: James J. Jeffries was the first great heavyweight champion of the gloved era. As with Sullivan, there’s little existing footage of him, and what is available is difficult to see. Jeffries retired undefeated as heavyweight champion, a rarity for any age, but was lured back roughly six years later when race-fueled bigotry against heavyweight champion Jack Johnson was at an all-time high.

According to The Sweet Science’s Aaron Tallent, some consider Jeffries to be the strongest heavyweight champion ever as well as the most accomplished heavyweight to come along until Joe Louis burst on the scene almost 30 years later.

Regardless, Jeffries would be in deep waters against Ali. While the old-time champion would be a much better version of himself than the one Johnson shellacked in 1910, he wouldn’t be prepared for the skills Ali would bring to the ring.

Conclusion: Jeffries was tough and considered physically large for his time, standing nearly 6’2” and weighing roughly 225 pounds, but Ali was bigger, faster and would have a considerable edge using the modern rules of boxing. Jeffries would retire on his stool after the beating of a lifetime.

Verdict: Ali via Round 8 TKO

Jack Johnson

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Analysis: Johnson was the most controversial heavyweight champion before Ali came on the scene. He was the first African-American to win the world heavyweight crown, and he seemed to revel in the antagonism that came along with it during that time in American history.

As a fighter, Johnson was perhaps the best defensive tactician in heavyweight history. He could block, catch and parry punches like no one before or after him, and he had excellent power and sharp counterpunching skills to match. 

Conclusion: Johnson would fare well against champions such as Jack Dempsey and Rocky Marciano because he was so adept at turning his opponent’s offense into the avenue of their destruction. Against Ali, though, he’d face a fast and agile mover who could hit him from distances he’d be hard-pressed to counter from.

Verdict: Ali via UD

Jack Dempsey

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Analysis: Dempsey had the style and physicality to give Ali a tough fight. His bob-and-weave approach was similar to what Joe Frazier used to defeat Ali in 1971 when the two men met for the first time. Like Frazier, Dempsey touted high-octane power in his fists and had good speed, too.

But if the smaller and slower Gene Tunney could beat Dempsey twice, primarily by landing a straight right whenever Dempsey advanced, Ali could as well. Ali might not have been the technician Tunney was, but he was bigger, stronger, faster and more agile. Dempsey would get in close here or there and make things fun, but Ali would win the bout.

Conclusion: This one would be entertaining, but Ali would be too big, skilled and tough for Dempsey to overcome. There would be moments in the fight where Dempsey would stun Ali, perhaps even getting a knockdown. But Ali would outbox Dempsey and would probably knock him off his feet, too.

Verdict: Ali via UD

Rocky Marciano

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Analysis: Rocky Marciano is the only heavyweight champion in history to retire undefeated. The stocky, powerful mauler's style might give Ali moments of doubt throughout a fight. 

Marcicano was tough, game and used his strong legs to get an incredible amount of torque of his punches, especially his overhand right. Ali, while gifted with speed and athleticism, did have a tendency to fight with his hands down and pull straight back. Marciano would not land many punches early in the fight, but as the rounds wore on, he’d begin to make his mark.

Conclusion: Marciano was a resilient pressuring machine who never stopped moving forward, but Ali would outbox him in the early rounds. While Marciano would get better at landing punches as the bout progressed, it’s unlikely he’d do enough to win the fight.

Verdict: Ali via UD

Joe Louis

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Analysis: Joe Louis held the heavyweight championship for 12 years and defended it 25 times, both of which remain the best work of any heavyweight ever. He was nearly flawless offensively and became a great all-around fighter as his career progressed, especially after he suffered a loss to Max Schmeling in 1936 and corrected his habit of dropping his lead hand after throwing it.

Whereas Ali was a constant blur in the ring, Louis was a case study in efficient movement, daring his opponents to stand in front of him and fight. He had a propensity of being knocked down at times, but men who were close enough to do that were also close enough for Louis to hit back. Louis was perhaps the hardest, most precise puncher in heavyweight history.

Conclusion: No hypothetical fight in heavyweight history is more intriguing than Ali vs. Louis. While Louis struggled with excellent boxers who moved and kept him far away from them, Ali’s boxing ability was more centered around his physicality than tactile excellence. The fight would be a back-and-forth affair. Ali would box. Louis would stalk. At the end of it, we’d all argue over who we thought really won the fight because both men could make a case for it. 

Verdict: Ali via SD. The judges would give the nod to Ali, the naturally larger and flashier puncher who rallied late for the victory.

Mike Tyson

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Analysis: In his prime, Mike Tyson was a phenomenal talent. He had fast and heavy hands, and he employed a style perfectly matched with his athleticism and demeanor. Tyson threw smart combinations out of a peek-a-boo style that relied heavily on slips and blocks. At his best, he was great at it, perhaps even better than its first grand practitioner—Floyd Patterson.

But as much as Tyson is celebrated in popular culture today, he had numerous flaws Ali would exploit. In short, he relied too much on psyching his opponent out ahead of time, had trouble in fights where he was forced to move backward instead of forward and regularly self-imploded.

Conclusion: Ali wouldn’t be scared of Tyson. He’d make the shorter man chase him early before grappling him in close later in the fight. Tyson would get frustrated when he landed hard shots Ali could take, and he’d succumb to stinging Ali punches after the middle of the fight.   

Verdict: Ali via stoppage in Round 9

Evander Holyfield

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Analysis: Evander Holyfield had everything he would need to give Ali fits. He was a sound boxer, a rough brawler and fought with an adaptable style. Ali would not want to be lured into a slugfest with Holyfield. While both men had tremendous heart and iron chins, it’s difficult to envision Ali being able to out-tough Holyfield.

Still, Holyfield did have numerous flaws. He was a much better fighter as a heavyweight when his opponent would seek to engage him first. Fighters like Lennox Lewis, who chose to box carefully from a distance over the course of their two fights, posed problems for Holyfield. Moreover, Holyfield would sometimes try to prove his courage over winning a fight. 

Conclusion: Ali would use his legs versus Holyfield to make it more of a track meet than a street fight. Holyfield would have his moments. The two would stagger each other here and there, and Ali would get the worst of it more often than not. But Ali’s overall punches and sheer theatrics would give him the nod on two of the judges' scorecards. The other would have the bout as a draw.

Verdict: Ali via MD

Lennox Lewis

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Analysis: When he fought as trainer Emanuel Steward instructed, Lewis was almost unbeatable as heavyweight champion. His athleticism made his height (6'5") and long reach (84") more formidable. Unlike other super heavyweights such as Wladimir Klitschko, Lewis was a natural-born fighter—fluid in motion and sure of what did. 

Lewis was also a smart tactician—something he'd need against Ali. He knew not to get dragged into brawls against the likes of Holyfield and Tyson. Against Ali, he’d know he could win the fight by staying back and boxing from a distance with his long reach before clubbing Ali when he came in close.

Conclusion: At his best, Lewis was the total package. Ali wouldn’t be able to outmuscle him, and while he’d have the edge in speed, Lewis’ power and technical ability would wreak enough havoc to give him the nod in the end.

Verdict: Lewis via UD

Vitali Klitschko

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Analysis: The majority of fight watchers vastly underrate Vitali Klitschko. He was a dominant heavyweight champion who used his size, strength and intellect to inflict merciless drubbings on opponents.

Vitali didn’t enjoy the longevity his younger brother Wladimir has, but he never looked as beatable and roughed up shared opponents more thoroughly. Vitali lost a total of two fights in his career—one when he suffered an injury against Chris Byrd, and the other when he was hindered by a huge cut against Lennox Lewis. In both fights, Klitschko was ahead on the scorecards and appeared to be on his way to victory.

Like Wladimir, Vitali had excellent power, but it was a different kind. Where Wlad could separate opponents from their senses with one-punch explosions, Vitali would beat his rivals into the ground more like a hammer hitting a nail. His size, toughness and IQ would help him give Ali fits, and at 6'7", Vitali would make Ali punch up more than ever.

Conclusion: It would be a tale of two fights. Some in the room would see Ali darting and dodging while peppering Klitschko with fast jabs and flashy crosses. Others would see Klitschko landing the more telling blows, especially late in the fight when Ali would be a microsecond slower.

Verdict: Ali via split decision

Wladimir Klitschko

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Analysis: The younger of the Klitschko brothers, Wladimir is an impressive physical specimen. Standing 6’6” with an 81-inch reach, Klitschko is also a gifted athlete. He’s fast, lean and muscular and is always in shape and ready to fight. Along with his excellent jab, Klistchko carries legitimate one-punch power into every second of every round.

In Ali, however, Klitschko would be faced with a better athlete, one with a great chin, enduring stamina and underrated power and strength. Ali would likely surmise how to beat Klitsckho based on his two main weaknesses: his chin and his overbearing commitment to not throwing a punch unless he’s absolutely sure about it.

Conclusion: Klitschko would try to jab-cross his way to the win. It wouldn’t work against Ali, but Klitsckho would go the distance in a fight that is fairly easy to score. Ali would confuse Klitschko with punch patterns and keep the larger foe incapable of planting his feet.