LAS VEGAS — In an alternate universe, Amile Jefferson is still playing in the NBA. The 33-year-old gets on the court every practice, and guards the Celtics’ best frontcourt players.
He can still jump high, after all. He can still swat shots. The 6’9, former Duke University standout is very much still in peak athletic condition.
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But, in this world, Jefferson is an up-and-coming coach. This summer, he’s the jovial leader of the Celtics’ Summer League squad, the fiery coach who usually has a grin plastered across his face, but sometimes switches gears to become uber-intense — Joe Mazzulla-style.
“On a regular day-to-day basis, you just see me walking around – I’m very calm, very smiley, just easy to be around,” Jefferson told CelticsBlog in an exclusive conversation. “But, as a player, or when I’m coaching, that side gets unlocked, and then I get super competitive, and I’m a totally different person.”
Near center-court, Jefferson emphatically clenches his fist when Hugo Gonzalez sinks a three-pointer.
“That’s a foul, ref!” he belts each time he believes the whistle should have been blown.
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“I’m trying to let them know that I’m in the fight with them, that they’re not alone,” Jefferson said. “And making sure they can hear my voice, making sure they know that I can help them be organized, making sure that they know that I got their back. And whether it’s screaming out a call or coverage, or whether it’s just giving an encouraging word, when I’m out there, I’m locked in – and probably am a little bit of a different person.”
He pauses and smiles.
“A lot louder, I can tell you that.”
Inside Amile Jefferson’s journey from Celtics’ training camp player to Summer League head coach
Jefferson’s story is a fascinating one, because just a few years ago, he arrived at Celtics training camp as a player.
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In 2020, he signed an Exhibit-10 contract with Boston, but got diagnosed with COVID-19 on his first day of camp, which effectively ended his chances of making the NBA that season. That came on the heels of several years of grinding in the G League, which included stints with the Minnesota Timberwolves and Orlando Magic on two-way contracts.
After his time with the Celtics was cut short, Jefferson headed to Turkey, where he laced up for the Galatasaray Club. But, at 28 years old, while he was still in his athletic prime, an opportunity came along that changed everything.
Jon Scheyer, one of Jefferson’s closest friends and mentors, had accepted the job of being Duke’s newest head coach, and he wanted Jefferson, the only three-time captain in Duke University history, on the coaching staff.
Jefferson had to make a difficult choice: he was still dominating on the court — he recalls dropping 25 points and 15 rebounds in his last pro game in 2021 with a glisten in his eye — but this was Duke, this was Scheyer, and this was an opportunity almost impossible to resist.
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“It was really hard,” Jefferson said. “I was playing well. I thought there was a chance I could get back into the NBA at some capacity. I had training camp offers, which was crazy. My agent was not happy about it.”
There was no major injury. There was no urgent reason Jefferson had to walk away from playing. But the former NCAA champion knew that opportunities like that don’t come by often, and so he capitalized.
“It was fun to do something new and to be uncomfortable and to challenge myself — and that’s where growth happens,” Jefferson said. “And I always had a growth mindset, and I’m always trying to find ways to get better. And so for me, yeah, it was tough. But I knew it was the right thing to do.”
NEW YORK, NY – NOVEMBER 09: Duke Blue Devils head coach Mike Krzyzewski and associate head coach Jon Scheyer and Amile Jefferson Duke Blue Devils director of player development during the Champions Classic college basketball game between the Duke Blue Devils and the Kentucky Wildcats on November 9, 2021 at Madison Square Garden in New York City,NY. (Photo by Rich Graessle/Icon Sportswire via Getty Images) | Icon Sportswire via Getty Images
If Scheyer hadn’t made that call, Jefferson believes he never would have made the pivot to coaching that young.
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“Duke is definitely home, and home base,” he said. “And so if that didn’t happen, especially if that didn’t happen at the timing it happened that year, I’d probably still be playing basketball right now today, which is crazy how life and the world works.”
“Because I was in shape, I was in my basketball prime, I felt great — I was playing really well.”
Jefferson spent one season as an assistant at Duke and then joined the Celtics in 2023 when a coaching position opened up. That marked another difficult decision, but Scheyer encouraged him to take the role, as difficult as it was to leave Duke.
In Boston, Jefferson was first a member of the offensive team, and last year, pivoted to the defensive team. He also helps assistant coach Matt Reynolds determine when to use the coach’s challenge.
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“I always say that I got my PhD in basketball my first year here in Boston, and so it was really cool to do,” he said. “It was really hard to do because Duke is the best school, best program in college basketball – and Jon is one of my closest friends. But he wanted me to do it. He wanted me to learn. He knew I would get better, and so it was a hard decision to make. But it was a great one, and one that I’m grateful for. Grateful for Jon, and grateful for Joe [Mazzulla].”
Toward the end of this past NBA season, the decision paid off in another meaningful way: he learned that Joe Mazzulla had picked him as the next Summer League head coach.
And fittingly, as Jefferson coached his first game, Jon Scheyer and Jayson Tatum, Jefferson’s former Duke University teammate, sat courtside. Tatum cheered when Jefferson got called for a technical foul just 9 minutes into his coaching career.
“Passion,” said a mic’d up Tatum. “That’s what we call it.”
In Las Vegas, Amile Jefferson is prioritizing player connection
Serving as a Summer League a challenge that Jefferson has embraced, and also one that he’s uniquely qualified for. He, like most of the guys on the current Celtics Summer League roster, bounced around on training camp deals in hopes of carving out a spot in the NBA.
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In two Summer Leagues spent with the Magic, Jefferson averaged just 4.8 minutes per game. As such, he relates with the majority of the roster, with the many players who have seen limited on-court opportunities as they pursue their lofty dreams.
“I was them,” he said. “I played in three summer leagues. I know what it’s like to be fighting to make it. I know what it’s like to be undrafted. I know what it’s like to be in a new environment, learning a new system in three days, and then trying to apply it.”
As such, Jefferson exudes a palpable pride when he talks about his players.
Take John Tonje, for example. The 25-year-old is fighting for a spot in the NBA after being drafted 53rd overall in 2025. Last year, he was on a two-way contract with the Celtics. This year, he’s angling for one, but he’s facing stiff competition.
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“He’s one of the guys I’m most proud of because he wants to make it,” Jefferson said after the Celtics’ Wednesday night win over the Sacramento Kings. “And when a guy wants to make it, and when a guy wants to be in the NBA, that’s how you look. If somebody wants to know how hard it is to be in the NBA — you can all see how good he is. He’s given himself a really good chance. He is definitely an NBA player.”
Jefferson has stressed that message to Tonje. He’s taken the time to get to know all 16 players on the team, some of whom he was already intimately familiar with, some of whom he’s just getting to know.
“I’m trying to talk to all our guys, hit all of them, make sure their mind is right, and make sure that they understand where I see them,” Jefferson said. “And so for John, it was really just giving him his flowers of how I appreciate how hard he’s been playing. I truly do. I think it’s impactful. I think it’s something that guys can learn from. I think when you watch it, you can be inspired because all these guys are trying to chase their dream and fulfill something that they wanted to do since they were kids. So, to see guys going out there, working that hard and implementing that in the game is really cool.”
Milos Uzan, like Tonje, is fighting for an NBA roster spot, and he’s appreciated the way that Jefferson has taken the time to connect with him. The two have chatted about their respective runs to the NCAA title game — Jefferson with Duke in 2015, Uzan with Houston in 2025.
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Uzan, who signed an Exhibit-10 contract earlier this week, will join the Celtics for training camp, an opportunity he’s expressed heaps of gratitude for.
“Amile’s a good dude, man,” Uzan said. “I’m glad I’m able to play for him… It’s so much I’m learning.”
In our conversation, Jefferson made sure to point out that it’s not just him who is in an elevated coaching role at Summer League. He credited player development coaches God Shammgod Jr, Da’Sean Butler, and Nana Foulland for how they have handled their promotion to front-of-bench roles in Las Vegas.
“We have an awesome coaching staff, so we’ve been able to do some really cool things with them,” Jefferson said. “Sham, Da’Sean, Nana, in particular, have done an awesome job this summer league, and just finding their voice and really coaching hard and being invested in a way, and being creative and coming up with new schemes and new offenses. So I’m really happy to have those guys around. Really proud of the job they did.”
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Jefferson still gets a taste of the on-court competition
Jefferson is no longer in the physical throes of competition the way he was as a player, but as he crouches over at center-court at the Cox Pavilion, he sometimes forgets he’s on the sidelines: “My body, the way I’m moving, the way I’m talking, it feels like I’m out there, even though I’m not.”
During the year, he enjoys getting the opportunity to battle with players on the court. Sometimes, he takes on the task of guarding Neemias Queta and Luka Garza at practice. Other times, he shoots around with close friend Jayson Tatum. Last year, he was tasked with working closely with Nikola Vucevic, a former teammate of his in Orlando.
“It helps me scratch an itch,” Jefferson said. “And I think it’s really helpful for the guys because I can still move really well. I can guard them at a high level. I can show them things, talk through it, but also just get on the court and show them, especially defensively; coming over, helping, protecting the rim, things like that. I feel like I can still do it at a high level — not the level they’re at — but a level that can help them get better.”
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At Summer League, Jefferson’s responsibilities have temporarily shifted. He hasn’t spent much time on the court actually battling the players the way he does during the season. He’s been so focused on the big-picture X’s and O’s that he’s not lacing up and competing in practice the way he usually does.
Chris Cenac Jr., the Celtics’ 19-year-old first-round pick, joked that Jefferson has been avoiding guarding him.
“He’s been ducking,” Cenac told CelticsBlog with a grin. “I ain’t gonna lie. Yeah, he’s been ducking.”
Jefferson burst into laughter when asked about that notion.
“That’s actually funny,” he said with a smile. “I was talking to Matt [Reynolds] that, man, I forgot that I didn’t even get on the court with these guys to show them that I can actually still move and play. I’ve been coaching them, trying to coach them so hard. I’ve been worried about that, but Chris, Dillon [Mitchell], they’ll get welcomed to the Academy once training camp and all that stuff goes on. So, ask him again in like a month and a half.”
Under Jefferson’s leadership, the Summer League Celtics are 3-1. Despite having no lottery picks and only a few returners from last season, they only missed entry into the playoffs due to point differential.
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The players — from the biggest names on the roster to the ones that may not even see the floor — are grateful for the culture that Jefferson has established.
“You can tell he’s a winner,” said Hugo Gonzalez. “He got a lot of passion in basketball, and he wants to have things perfect. And I think he transmits a great message to everybody — of the ambition, of the competition, being hungry for 40 minutes of the game. I think he’s doing an amazing job.”
