His fall, such as it was, came when the company, too, faced dark days. His phoenix-like rise also coincided with the MMA boom, with Penn dominating the lightweight division just as the sport exploded in popularity.
But man, alas, is mortal. While the UFC can last until the end of time, Penn's career cannot. As the end nears—and this Saturday's showdown with Rory MacDonald may end up being the final significant fight of his illustrious career—it's time to take a look back at the moments that made the "Prodigy" one of the most memorable fighters in MMA history.
The following snapshots of a fighting life, in chronological order, are the moments we'll always remember. Click with me for the best of BJ Penn.
BJ Penn vs. Din Thomas
June 29, 2001
"It feels like a title fight."
That's how announcer Mike Goldberg described this contest, a bout between a UFC newcomer and a fighter in just his second bout inside the Octagon. Today, it would be ridiculous. Yet somehow, in 2001, that hyperbole felt true.
It was a different time, the dawn of the Zuffa era. A fighter like Din Thomas could step into the UFC for the first time and already be considered the top competitor in his weight class. BJ Penn, in just his second bout, could be considered among the best based on jiu jitsu credentials and hype alone.
"This fight is going to prove if the talk is just talk," then-champion Jens Pulver said. It didn't take long for Pulver to get his proof. Penn caught Thomas flush with a knee right to the face and was one step closer to the lightweight title.
BJ Penn vs. Caol Uno
November 2, 2001
Caol Uno was arguably Japan's best fighter in November 2001. Someone forgot to tell BJ Penn. After an ill-timed flying kick from Uno, Penn pounced, knocking him out in just 11 seconds.
Believe it or not, it wasn't the KO that resonated at the time. It was Penn's passion, exemplified by his immediate departure from the Octagon and sprint up the ramp to the back. Eventually, he would return to a rousing ovation to get his hand raised. To me, it's the definitive BJ Penn moment and a night I will never forget.
BJ Penn vs. Jens Pulver
January 11, 2002
Announcer Jeff Osborne might as well have been speaking for the entire MMA community when he told Jens Pulver, the reigning UFC champion, "Jens, I hate to say it buddy, but I wouldn't want to be you."
Pulver, after all, seemed like a mere stepping stone, just another obstacle in the path to BJ Penn's eventual crowning as the top lightweight in the world.
Pulver, however, had other plans. Over the course of five rounds, heart and grit outdueled Penn's talent and ability. It was the kind of fight moralizing sports writers love. For Penn, it was an important lesson, one that would later propel him to greatness.
Pulver summed the night up in a single sentence: "Sometimes, hype ain't enough."
BJ Penn vs. Takanori Gomi
Rumble on the Rock 4
October 10, 2003
In retrospect, this was a battle for all-time supremacy in the lightweight division. Penn would go on to be the longtime UFC champ. Gomi was the Pride standard bearer for years. At the time, however, it was nothing of the sort.
Yes, it was a big enough fight that UFC president Dana White flew to Hawaii to bear witness. But Penn was fresh off a soul-crushing draw with Caol Uno, failing for the second time to become UFC champ. Gomi had lost his Shooto title to Joachim Hansen. Both were looking for a big win to get back on track.
In the end, there can be only one. And that one, in the lightweight division at least, is BJ Penn. He took Gomi down almost immediately, and that set the tone for the whole fight. The Japanese star was game, but Penn was just too strong on the mat, finishing things with his patented rear naked choke in the third round.
Gomi wouldn't lost again for almost three years, becoming Pride champion in the process. Penn too was on to better things and a title belt of his own.
BJ Penn vs. Matt Hughes
January 31, 2004
White had a different idea—if Penn was going to go up in weight, why not all the way to the top? Why not fight Matt Hughes?
Penn, of course, was game. He had held his own in training against bigger wrestlers like Randy Couture and Matt Lindland. He was confident he could handle Hughes on the mat, confidence that was justified with a first-round submission and his first ever world title.
After the fight, Penn shocked the world one more time by kissing Hughes right on the lips to celebrate his win.
BJ Penn vs. Lyoto Machida
K-1 Hero's 1
March 26, 2005
It's moments like this one that make BJ Penn a legend. In the cage, he wasn't always perfect. He lost the big one as often as he won it. But who else in MMA history would have the cojones to jump all the way from lightweight to heavyweight?
And I'm not talking about for a comedy fight with a fat sumo or a tomato can. I'm talking a fight with one of the best in the world, more than 50 pounds above your best weight class.
The answer is BJ Penn—and only BJ Penn.
No, Penn couldn't best Lyoto Machida. But he gave it a heck of a shot, taking the future UFC champion at 205 pounds to a decision that goes right alongside his title wins as one of the most incredible fights of his career.
Think about that when one of today's stars refuses to fight an opponent one weight class above him. There are fighters, and then there is BJ Penn. He stands alone.
BJ Penn vs. Joe Stevenson
January 19, 2008
More than six years after his first shot at the lightweight title, Penn finally strapped gold around his waist. Joe Stevenson was the unfortunate victim, a man with no chance against a fired up and motivated Penn.
By the end of the first round, Stevenson was bleeding buckets. As blood poured out of his skull, Penn went about his business, finishing things with a rear naked choke in the second round.
Stevenson, however, wasn't the champion going into the fight. Penn's old nemesis, Sean Sherk, had been "the man" in the division until a failed drug test cost him the title. It was Sherk, sitting with Joe Rogan and Mike Goldberg cageside to call the fight, who was on Penn's mind immediately after the fight.
"Sean Sherk," he told the former champion and the crowd post fight. "You're dead."
BJ Penn vs. Sean Sherk
May 24, 2008
Penn spared no words, telling the world exactly what he thought about Sherk's failed steroid test. And Sherk was not pleased.
"I've never fought anyone I hated before," Sherk said before the fight. "This fight with BJ is personal."
All the trash talk seemed to motivate Penn. After the most intense war of words in his long career, he delivered on his big talk in a major way. He stopped Sherk with strikes at the end of the third round, and then things really got weird.
After pausing for some trash talk and licking Sherk's blood off his gloves, he sprinted across the cage to run his hand down the face of his fallen foe. He then licked it clean of blood, wanting, I guess, one more taste of his hemoglobin.
"You just get caught up in the moment trying to beat somebody up or kill them," Penn told Asylum.com. "I don't think that is really for the fans, just for myself. At that moment you cross over the barrier.
BJ Penn vs. Diego Sanchez
December 12, 2009
When BJ Penn is at the top of his game, it's a scary sight to behold. There are few others in the history of the sport who can take another top fighter, a legitimate contender, and make him look like absolute trash. BJ Penn can do that to a man.
Diego Sanchez is no joke. The former The Ultimate Fighter winner is as real as they come, with wins over Nick Diaz, Clay Guida and Kenny Florian on his substantial resume.
Sanchez, however, had nothing for Penn. The champ beat him so bad his face was grotesquely swollen and puffy. A giant cut above his left eye redefined "gaping."
Sanchez showed tremendous courage and heart, absorbing a beating that would have caused most fighters to quit. Eventually, the cageside doctor did that for him, but not before Penn administered one of the worst beatings in UFC history.
BJ Penn vs. Matt Hughes
November 20, 2010
Penn's second fight back in the UFC in 2006 was a title bout with Matt Hughes and, more importantly for both men's respective legacies, a chance for Hughes to even the score. He did just that after a rib injury slowed Penn in the second round.
Four years later, with Hughes most certainly past his prime, UFC officials helped set up a rubber match to decide once and for all who was the better man.
This time, Penn left little doubt. In less than 30 seconds, it was, to steal a line from announcer Mike Goldberg, "all over." Penn caught Hughes with a right hand down the middle and pounced, as only he can, for the stoppage.
Penn, in shades of the Uno fight at UFC 34, immediately sprinted out of the arena. Later, he would confirm to UFC.com that it was indeed a homage to one of his most memorable moments.
"I've been trying to do a fight like the (first) Uno fight for the last nine years and it just never came out that way. So when this fight (with Hughes) ended up ending very quick with a knockout, I was pumped up, I started screaming in the ring for a little bit and I was like 'here it is, here's my chance. I'm gonna get out there and I'm gonna do it – Elvis is gonna leave the building.'"