Celtics officially remove ‘interim’ tag on head coach Joe Mazzulla and cut ties with Ime Udoka

Joe Mazzulla has guided the Celtics to a 42-17 record and is preparing to coach in the All-Star Game.Matthew J. Lee/Globe Staff

As Joe Mazzulla flew to Salt Lake City Thursday to begin preparations to coach in Sunday’s NBA All-Star Game, the Celtics took a big step in solidifying their future while moving on from a difficult time in their recent past.

The team announced that Mazzulla, who was named interim coach in September following coach Ime Udoka’s suspension for violations of organizational policies, had been elevated to head coach and received a contract extension, and that Udoka was no longer a member of the franchise.

“It’s going to be really hard to win, and the hardest things to do would be coaching, looking behind you and looking over your shoulder,” Celtics president of basketball operations Brad Stevens said Thursday night. “It’s about looking forward and if you’re in a Game 7, know that everybody in the organization believes in you, and that uncertainty erases. Like, you’ve earned that, and so I thought that was really important.”

According to league sources, Udoka had received a one-year, unpaid suspension because of an improper consensual relationship with a subordinate team employee.

The decision to permanently promote Mazzulla is hardly surprising. He has guided the Celtics to the best record in the NBA (42-17), gained the trust of his players, and put the team in position to win its first championship since 2008. And league sources stressed in recent months that Udoka’s time with the team was over, despite the fact that he had been suspended rather than fired. Still, there was a belief that, primarily for legal reasons, this move would not become official until Udoka’s suspension ended June 30.

Mazzulla has officially been elevated to head coach, and has received a contract extension.Erin Clark/Globe Staff

But now that potential distraction has been lifted, and the Celtics will move forward. Mazzulla said he found out about his promotion Tuesday, and that the deal was finalized following Wednesday night’s win over the Pistons.

“It is pretty wild,” Mazzulla said. “A lot going on, but I’m just grateful. Grateful that not many people get an opportunity to experience this, especially in the manner that I am with the players that I’m able to coach and the people I’m able to work for. And it’s for the Celtics. It’s a dream come true, for sure.”

It has been a meteoric rise for Mazzulla. After his playing career at West Virginia, the Johnston, R.I., native worked as an assistant at Division 2 schools Glenville State and Fairmont State from 2011-16. He was then hired as an assistant by the Celtics’ G League affiliate, the Maine Red Claws, where he made an impression on then-Celtics president of basketball operations Danny Ainge and Stevens, the head coach at the time.

Two seasons after that, he came back to Boston as a Celtics assistant.

Mazzulla was the lone member of Stevens’s staff to be retained when Udoka was hired in the summer of 2021. But last year, he was not even one of the three assistants who sat on the bench alongside the head coach. Still, it increasingly became clear to Celtics brass that he was a rising star.

When assistant coach Will Hardy was hired to coach the Jazz last summer, Mazzulla was elevated to a lead assistant role. And when Udoka was suspended in September, Mazzulla was named interim head coach.

“I always knew exactly where I stood, even though it was an interim position,” Mazzulla said. “I knew I would get a fair shake, an opportunity. I knew that I was going to be able to do what I thought would give you the best chance to be successful because of their standard and their communication and how they treated me as an assistant. I just felt comfortable regardless.”

Initially, the transition was slightly bumpy. The players respected Mazzulla, but several also were frustrated by the lack of explanation about why Udoka — who had guided the team to the brink of an NBA title last June — had been pushed aside.

When the Nets fired coach Steve Nash after a 2-5 start, Udoka reportedly was lined up to be named as his replacement, eliciting more confusion from Celtics players.

“Obviously, we wish he was here,” Marcus Smart said then. “We have no control over that. I guess it was deemed that whatever happened was enough for him not to be the coach here, but I guess not enough for him [not] to be a coach anywhere else, obviously.”

Mazzulla has guided the Celtics to the best record in the NBA.Matthew J. Lee/Globe Staff

The Nets front office ultimately decided against hiring Udoka and gave interim coach Jacque Vaughn the permanent role. At the time, Mazzulla said he understood his players’ unease about the situation and vowed to be available to discuss any concerns. But he said he would also remain focused on his task.

If there was any remaining uncertainty about his future with the team, it has now been washed away.

“I know Joe will work his tail off, I know Joe will give everything he has to lead, and I know he gives a damn about everybody in that locker room,” Stevens said. “Like, he really cares. It eats him up when something doesn’t go well individually for a guy. It eats him up when he feels like he’s let the team down. He’s not going to ever come in and say, I wish this person or this person or this person would’ve done their jobs better. He’ll always say the opposite.”