Not long ago, a photograph of the basketball player Jimmy Butler riding a horse across a street in Miami surfaced on the Internet. The photo was oddly striking, not only for its incongruous imagery—man in white tank top, sneakers, and cowboy hat; skyscrapers, graffiti mural, cars; random dude beneath an umbrella in the background; large animal—but also for the shape of Butler atop the horse, a harmonious arrangement of inverted curves. There was every reason to think it was fake, or some sort of stunt. No related photos or videos emerged, no rumors about a six-foot-seven-inch celebrity on the back of a beautiful black Andalusian moseying around downtown. The street lights in the photograph were off, and the cars didn’t appear to have license plates. When I asked people who keep tabs on these kinds of things, none of them seemed to have heard of it.

The explanation, which emerged on Thursday night, was fairly prosaic: Butler was shooting a commercial, in which he wins a game of H-O-R-S-E sitting atop (yes!) a horse. But it had been reasonable to imagine more outlandish possibilities. Jimmy Butler is not like most basketball players, or most people. There was a chance that he was just riding a horse around Miami. It wouldn’t have been the most surprising thing he’s done.

This is Butler’s time, or should be: spring, the start of the N.B.A. postseason, when Butler transforms into Playoff Jimmy and leads the middling Miami Heat to glory, as sure as the daffodils. Four years ago, inside the N.B.A.’s pandemic bubble, Butler led the fifth-seeded Heat to the N.B.A. Finals, where the team lost to the heavily favored Los Angeles Lakers. The bubble is also where Butler launched his coffee company, Bigface, using his personal French press and charging players twenty dollars per cup—cash only, no change. (Bigface is now a coffee and life-style brand.) And the bubble is where Butler received a disturbance complaint for making loud banging sounds in his hotel room at four in the morning. He was dribbling a basketball while performing his daily pre-dawn workout.

Two years later, the Heat nearly made the Finals again. Butler, who’d averaged a little more than twenty-one points during the regular season, averaged more than twenty-seven during the playoffs. He was hampered by a bad knee during the Eastern Conference Finals, against the Boston Celtics, but, when the Heat faced elimination, in Game Six, on the road, he scored or assisted on sixty-eight of the team’s points, nabbed four steals, and grabbed nine rebounds. The legend grew.

Last year, the Heat barely made the playoffs; Miami was almost eliminated during the play-in tournament by the lowly Chicago Bulls. Then, as the bottom seed, the Heat destroyed the top-seeded Milwaukee Bucks, defeated the New York Knicks and the Celtics, and returned to the Finals. Butler, who’d been a good but not great player during the regular season, became unstoppable—stronger, somehow, more accurate, more tenacious. The nickname Playoff Jimmy was born.

Butler scoffed at the moniker—“I just be hooping,” he said—but the phenomenon is hard to refute. Butler averages more points, rebounds, assists, steals, and blocks during the playoffs than he does during the regular season, and that’s only one indication of his impact on the Heat when the stakes grow. His teammates, several of whom were undrafted players who made it to the N.B.A. via the developmental G League, cited Butler’s example—his discipline, his confidence, his mix of encouragement and pettiness—as a reason they, too, were suddenly playing like a bunch of ragtag Michael Jordans.

And yet it can be hard to tell, sometimes, whether Butler is the best teammate in the history of the N.B.A. or a bit of an asshole. Probably he’s both. He gets in fights, responds to slights, sometimes jaws at his own coaches. When he thinks his teammates aren’t working as hard as he does, he has been known to humiliate them. He’s played on four N.B.A. teams, and has not always made the smoothest of exits. The general consensus is that he’s not for everyone, and that he has found, in the Heat—with its militaristic and spiritual team president, Pat Riley; its genius coach, Erik Spoelstra; its like-minded star Bam Adebayo; and its collection of overlooked players—his home. In Miami, they call it “Heat Culture,” and the team has written the creed onto the floor beneath the basket: “HARDEST WORKING. BEST CONDITIONED. MOST PROFESSIONAL. UNSELFISH. TOUGHEST. MEANEST. NASTIEST TEAM IN THE NBA.” This can be annoying—all that preening about hustle, as if no one else plays with intensity and heart—but, like Playoff Jimmy, it isn’t entirely a myth. You can see it in the way players dive for balls, fight through screens, bully their way to their spots. You can see it in Butler most of all.

He grew up in Tomball, Texas. When he was thirteen, he got into an argument with his mother, and she kicked him out. He went from couch to couch, and then from junior college to Marquette. The loneliness that he must have had to overcome can be wrenching to think of. But that’s not the story Butler tells. Shortly before Butler was drafted into the N.B.A., in 2011, the ESPN writer Chad Ford asked him about his stretches of homelessness. Butler told Ford, “I’m just asking you, don’t write it in a way that makes people feel sorry for me. I hate that. There’s nothing to feel sorry about. I love what happened to me. It made me who I am. I’m grateful for the challenges I’ve faced. Please, don’t make them feel sorry for me.” Butler was the thirtieth player taken in the draft that year, the last pick of the first round.

Butler credits his success to the enormous amount of work he has put in. “I wasn’t always a really good player,” he has said. “I just worked harder than everybody. I just played harder than everybody.” He also says that he cares about winning more than anything. Most N.B.A. players say these things, but Butler, at his best, plays with a ferocity that makes you believe it. The strange thing is that losing doesn’t appear to unnerve him. There is an openness to him, a playful curiosity, that seems connected to his competitiveness. He seems to believe that people aren’t stuck where they are.

He plays backgammon, talks trash about Uno, and is never far from a set of dominoes. He told Rolling Stone that he’s working on a country-music album, and that he has sixty songs so far. (He started playing country music to troll his teammates, he said, who were playing hip-hop too loud.) He goes to Colombia and Peru to source coffee beans, hangs out with the soccer player Neymar, has befriended the young tennis star Carlos Alcaraz, and once did a stint as a ball boy at the U.S. Open. After the Heat failed in their pursuit of a trade for the superstar Damian Lillard, who was eventually sent to the Bucks, Butler showed up at the Heat’s Media Day wearing painted fingernails, several face piercings, and straightened hair that swept across one eye: Emo Jimmy. The year before, he’d come to Media Day in magnificently long dreadlock extensions. The picture taken that day is used as a player’s official head shot for the rest of the season, and so, all year, the image of Emo Jimmy has run next to starting-lineup announcements, highlight packages, and more. Emo Jimmy made another appearance later in the season, in a Fall Out Boy music video. Winning might be everything to him, but it’s not the only thing; and, in fact, he loses a lot. It doesn’t seem to change his sense of who he is or what he does.

This season, Butler has averaged twenty-one points per game, ranking him thirty-third in the league. The Heat have struggled with injuries, including to Butler; by mid-March, they had used thirty-four different starting lineups. But no one counted them out as a looming threat to the more obvious contenders. Around the All-Star break, the Heat began winning—they went 5–1 on one tough road trip, and 9–2 during an eleven-game stretch—and Butler seemed to round into form. The team’s defensive intensity increased; Butler started forcing his way to defensive stops. The Heat moved up the standings. One day, in late February, a reporter for Bleacher Report, Chris Haynes, found Butler sitting at his locker after a game, listening to the singer Malia, crooning along to her songs “Small Talk” and “Poet.” Haynes wanted to know how Butler flipped the switch, seemingly at will, whenever the playoffs were on the horizon. “You mean how can I turn into the greatest basketball player in the world all of a sudden?” Butler told Haynes. “I don’t know, man.”

It’s reasonable to wonder why Butler, for all his passion about winning, isn’t at his best for more of the year. The Heat, after all, would have an easier path to the Finals if they put together a better regular-season record, and earned a higher seed. (The Knicks’ Josh Hart recently joked that Butler spends the regular season doing “side quests,” before the “main quest” of the playoffs.) But it might be impossible to sustain the fervor of Playoff Jimmy all the time. It’s also reasonable to point out that a degree of luck has been involved in Miami’s surprisingly long playoff runs. Butler’s less famous teammates surely do draw confidence from their on-court leader, but their sudden ability to hit three-point shots during the playoffs may also have been a random gift from the basketball gods.

This season, as the playoffs have drawn ever nearer, the Heat have stumbled, and Butler has, too. This past Sunday, the Heat played the Indiana Pacers, and a win would have propelled Miami ahead of the Pacers in the standings, possibly allowing the team to avoid the play-in tournament. Miami lost by two. Butler had a statistically impressive game—twenty-seven points, seven rebounds, and eight assists—but looked oddly flummoxed on the floor. A similar thing happened against the Atlanta Hawks two days later. This time, the Heat eked out a win, in double overtime, but Butler looked uncharacteristically lost in the clutch, holding on to the ball too long, turning it over with a chance to win and six seconds left in the first overtime. One of these days, that might happen in a crucial moment during the playoffs, and Butler’s heroic image may dim, at least a little. Or maybe Miami’s playoff luck will simply turn. Butler is thirty-four now, and this can’t last forever. When it’s over, those of us who saw it will have to tell people the legend of Playoff Jimmy, and how much fun it was to behold. ♦