NEW YORK — Luke Kornet walked onto the floor at Madison Square Garden and requested Billy Joel as he worked out on the opposite side from Sam Hauser and Payton Pritchard. A sparse showing at a late-season shootaround allowed him to shoot his threes, work into hook shots before practicing contact and rebounding with Celtics assistant Amile Jefferson. Piano Man and Vienna played overheard, songs unfamiliar to team trainer and DJ Zay Covington, who’s grown used to learning new music from Kornet and the other bench players.

“We let everybody be who they are,” Derrick White said in a recent podcast appearance. “We don’t judge anybody. If you want to be goofy jokes like Luke, we embrace that.”

Kornet, the first two-way player with the New York Knicks in 2017-18 after the contract’s creation, arrived at their arena for a game that season in his black Toyota Camry. Security stopped Kornet at the entrance and needed to call to confirm his identity. He spent most of that season with the G-League Westchester Knicks, so he understood and forgave the disruption. They joked about during his ensuing visits. Security knew him later on from the scratches on his fender.

“I’m like no, I’m actually one of the players, I promise, ” Kornet told CLNS Media inside MSG in April. “I literally actually Googled myself to try to confirm to the guy.”

A breakout season

When the Celtics meet the Knicks at MSG this weekend later in their second round playoff series, they might not recognize him again. The former floor-spacer has turned into a put-back dunk, post hook shot-hitting physical force for Boston after playing a finesses and deferential role in the past. The Celtics see him as an x-factor. A way to play bigger, rebounding and defensive lineups that don’t lack offense as the league turns toward double-big.

Kornet kept that high school Camry when he signed with the Chicago Bulls, and drove it to meet the Celtics in Milwaukee when they acquired him at the 2021 trade deadline. He played briefly, fewer than 10 minutes, in four returns to Madison Square Garden since joining Boston between 2021-24. His showing this February was truly unrecognizable. Stronger. More forceful. More aggressive. Kornet never used to play for himself. He changed that mindset over the past two seasons and started attacking more.

“Part of it was definitely in the weight room and stuff, putting on some weight,” he said. “I feel like a lot of it for me was a transition in terms of like how I used to see the game a certain way and now I’m looking at it through a different lens. Just always physically bringing the energy, and then I think trying to seek the contact and initiate contact, where traditionally I was more playing the game, mentally, in terms of positions of everyone on the floor and now I think just embracing the one-on-one or more body-to-body physical part of the game.”

With Kristaps Porziņģis a late scratch due to an illness, Kornet started and stunned a Knicks team that badly needed the game for standings and morale purpose after falling to the Celtics in an opening night blowout. Kornet dropped 14 points, made all seven shots and grabbed 12 rebounds while blocking three shots. They knew him now.

The Celtics grew to recognize Kornet’s impact in the years since too. But it’s changed. The Knicks and Bulls signed him as a stretch five. He transitioned into a screening and passing role player who attempted few shots into his Boston years. But the Celtics’ coaching staff saw him as capable of more beginning last season. Assistants Charles Lee and Jefferson, new additions to the staff, convinced Kornet the benefits of playing more aggressively and thinking about basketball differently.

“When you catch it in the seam, looking to see if you can score, looking to see if you have a shot,” Jefferson told CLNS. “And then if they take it away, he’s such a good passer and he has such a good feel and mind for the game that you can make the right read behind the defense. So just getting him to be more aggressive on that end, and then you know the other biggest thing was just getting him used to the physicality. So watching him on film, making sure that he hits first or that he draws a line in the sand … he does a lot of things for us defensively where he’s guarding different positions, so just getting him to see that and feel comfortable with it.”

A powerful partnership

Jefferson, a former Jayson Tatum teammate at Duke, continued that process this year as the results flourished. The Celtics started Kornet in the preseason with Porziņģis while Al Horford rested. It drew him valuable reps with Tatum and the other starters, who pulled attention away from Kornet so he could beat smaller defenders in the post, roll for finishes and put backs. If defenses gave those to him, he needed to take them.

Kornet became an effective spot starter, one of the most consistent offensive rebounders in the NBA and in a stunning development — only Jamal Murray and Nikola Jokić surpassed Tatum and Kornet’s pick-and-roll efficiency. Kornet saw the stat, posted by Owen Phillips, in March.

Luke Kornet has been one of the most impactful bench players this season. Cs are steam rolling opponents when he’s on the court (+11.6 Netrtg.)

He’s got an undeniable chemistry with Tatum, which shows in their pick & roll numbers — #2 most potent combo behind Murray/Jokic pic.twitter.com/yRgIQCiQvj

— Owen Phillips (@owenlhjphillips) March 21, 2025

“It was pretty strange to see,” Kornet told CLNS. “You’re not really thinking about it. I do feel like me and J.T. have been able to grow in chemistry and honestly, I think a lot of it is a credit to him and his growth and development … then I’ve been able to develop more chemistry of how exactly to hold the reads or I think getting better at recognizing how to get to your fastball based on who’s on the court and what that’s gonna look like based on their coverage and our personnel and stuff like that of what the advantage is. It’s cool to see. Yeah, obviously, there’s great company in that, but it’s funny, you’re just doing it one possession at a time and that’s just what ends up coming out at the end.”

Kornet, never expecting any role on the team, began realizing midway through the season that his playoff minutes wouldn’t be in question this year. The Celtics played him in 73 games for 18.6 minutes per night, making him their wrinkle following a championship run. Joe Mazzulla said in the preseason that Kornet had a significant summer growing his offense, already held enormous trust in the coaching staff for his ability to play different defenses and got stronger. Kornet, who had offers from multiple other teams last summer, including a lucrative one from Utah, returned to the Celtics on a one-year, minimum contract due to his familiarity with the team, winning a championship and having the chance to return alongside all but two teammates from the run.

Boston decided to lean into its double-big lineups, and by playing Kornet with Horford together, constructing an effective pairing between former Knicks Porziņģis and Kornet, even trying Neemias Queta and Kornet sometimes, the Celtics developed a physical lineups that the team believes made them better than last year.

They’re more prepared for playoff opponents like the Orlando Magic that will try to beat them up, play bigger and control the boards. The Knicks could become the next to do that in round two with big men Karl-Anthony Towns and Mitchell Robinson, who played together more often in round one against Detroit and dominated the glass.

“It’s funny, because I do think I’ve come to terms with that a little more,” Kornet said. “I guess it doesn’t change a whole lot in terms of what you’re actually doing, but … it’s feeling like an increased sense of responsibility and accountability for myself. Especially with the playoffs …  how the league’s changing somewhat and the type of teams we’ll be playing, I think just recognizing the importance of bringing that physicality and having that presence and that’s a dynamic that our team can really be served from. So I do think it’s a bit of ownership of that that I’ve definitely grown (in) and I’m looking forward to doing whatever I can to help us win.”

Changing his game

Kornet’s willingness to not play served him across recent seasons, because in a crowded front court he often wouldn’t. He played well when called upon for narrow contributions, screening and dropping on defense. The shift toward becoming more important didn’t happen overnight. It started in the weight room, where increased muscle improved his health and post play, where he moved to in 2022 after shifting from the three-point line. Kornet attributed injuries that affected his shot and a different role in Boston for why he changed his game.

Jefferson began mimicking opponents in their workouts, how they’d guard him in actions based on opponents, then use his own 6-9, 200 pound frame to challenge Kornet, who’s big and strong, he points out. 7-1, 250 lbs. Pad work, getting into an opponent’s legs on box outs and film sessions with Jefferson drove Kornet’s breakout year.

Of course, it came with Kornet’s patented levity.

When he and Jefferson finished their pregame work this year, teammates stopped what they were doing. Players and coaches rose to their feet as Kornet approached the free throw line with the ball. They started clapping, building more loudly as Kornet palmed the ball and raced downhill, throwing down a windmill dunk as applause continued. Horford raised the roof watching on the baseline. It became a nightly pregame tradition.

“I played against Luke, so I’ve seen him before, but to actually work with him, it’s been a joy,” Jefferson told CLNS. “The energy he brings every day to practice, to shootarounds, to games. It’s infectious. It grows on people and so, for me, it’s just been an honor and we implement his style into everything he does, so it’s pregame shooting, we get people clapping. He has a lot of fun playing the game and it’s cool to me to see him having a lot of fun doing hard stuff.”

Earning trust

The Celtics exited Miami in February following Kornet’s MSG breakout having finally strung wins in six of their last seven and two straight since an awful blowout loss to the short-handed Mavs following the Luka Dončić trade. Horford, asked about the Celtics getting back to themselves in the locker room, brought up Kornet unprompted. He’s been key, Horford said, building the identity they want to play with through his rim protection. Horford saw teammates following Kornet’s lead and inspiring them to increase their level.

It’s remarkable, beyond the changes in his game from three-point shooter to rolling post presence, how much the Celtics grew to rely on him following his arrival as what amounted to a trade throw-in at that 2021 deadline. Boston signed him to a G-League contract the following summer, so he spent most of that year in Maine. There, he grew to become less invested in his own success, which made him a perfect complementary player. Jefferson still sees him as capable of shooting, pointing out his free throw percentage and how often they practice threes. The Celtics just don’t need it.

“We don’t really talk about it much, but the thing I think he’s done is he embraces his role,” Jefferson said. “He’s done that to the 10th, 100th degree whatever you want to say … What we need him to do, he does and we still shoot and we still work on those things and you can tell by the free throw line jumper … So that that stuff is still a part of his game. It’s just, he does what needs to be done for us to win.”

Eventually, the Celtics began stressing the need for more from him. More often this season, games where Kornet started began with him rolling for layups and dunks over and over.

The screening, which he credited to work he did with Zach LaVine during his time in Chicago, remained stellar. Kornet finished this season tied for 15th with 190 offensive rebounds alongside Jonas Valančiūnas.

“The leap that he’s taken this year and what he’s provided off the bench on the nights that he’s had to start,” Tatum said in April. “Our connection in the pick-and-roll, I’m in constant communication and talks during the game, on off days and whatever, and Luke just has a great feel for the game. He’s such a selfless player. He’s always looking to get me open off-ball, on-ball. I trust him so much when they double me or if the big is up to touch, throwing the ball to Luke in the seams and obviously, him being a rim threat for lobs. It’s been one of the more successful things for our team this year is me and Luke on the floor together and being in actions together.”

A playoff x-factor?

The numbers show that. Boston posted a 122.0 offensive rating when Tatum and Kornet played together this year, outscoring opponents by 15.8 points per 100 possessions. That offense would lead the league, as would their 106.2 defensive rating — just ahead of the Thunder. As of March, they posted 1.33 points per possession in the pick-and-roll. Kornet finished with 1.33 PPP as a roller for the season, in the 87th percentile of NBA players.

That led Mazzulla to make as many Tatum-Kornet minutes happen as possible in a playoff setting, which required altering his rotations some. The combination didn’t achieve the same pop, Orlando able to switch everything and slow Boston’s bigs with competitive defense from the guards. Jonathan Isaac played some zone off the bench, negating those rolls, but Kornet still shot 63.6%, grabbed 1.2 offensive rebounds per game and threw down a put-back dunk over Paolo Banchero in Game 4. He blocked two shots in the series, including Banchero’s, and started one half with Porziņģis in foul trouble. It wasn’t a breakout, but proved to be what the Celtics needed.

Now, against New York, Kornet should be able to slip out of more double-teams, utilize his passing in the post and will be needed to win a tight rebounding battle against the Knicks. The coaches trust him, teammates do as well, crucial to his ascent as Mazzulla pointed out.

And the crowd loves him. Sam Hauser called for them to bark like Kornet often does after a big play. More often, Luuuuuuuuke rains down from the balconies after he puts back a shot. And with Tatum scorching coming out of round one in search of another championship and step in his journey as one of the game’s great players, he found an unlikely sidekick whose career has blossomed through an almost exclusive focus on getting Tatum open.

For Kornet, a player formerly used to sitting this time of year, that dynamic has made him realize how tangible his role proved in the team’s winning this year. And how much they’ll need him to win another championship.

“I think that’s been a big part of our ability to win games,” Kornet said. “And we’ve gotten better and better every year.”