Cassell on what makes Mazzulla a great NBA coach: 'He is looking at things differently than other coaches'

In 2023-24, Mazzulla coached his first full season, and the C's became the most dominant team in the East and the entire league. Boston assistant coach Sam Cassell, who joined the Celtics staff in 2023, shed light on what makes Joe so effective.

"Joe Mazzulla makes it very competitive around and between them guys," says Cassell. "He listens to his players. He listens; he's not afraid to challenge guys; he doesn't get too high or too low. We could lose a couple of games, and he would be like, 'Wow, that was a great game; we just lost, and so what? Look past the loss and how much better we got even though we lost. So he looks at things different than a lot of coaches in this league that I've been around."

No experience, no problem

Mazzulla's success in Boston mirrors the journey of another coach who once faced skepticism due to his lack of head coaching experience—Steve Kerr. When Kerr took over the Golden State Warriors in 2014, he had no prior head coaching experience but quickly turned the team into a dynasty.

Similarly, Joe's cool and calm demeanor allowed him to thrive under pressure and guide the Celtics to their first championship since 2008.

"People don't just know him; people think he's an uptight guy, but he's far from uptight. You gotta know him to really realize who is Joe Mazzulla... He's been awesome for me as an assistant coach," Cassell said.

Winning title No. 18 for Boston proved the 36-year-old's ability to connect with his players, adapt to challenges, and maintain a steady focus despite his zero coaching experience. Mazzulla's approach is welcomed not only by the players but also by the coaching staff.