Oct 10, 2025; Toronto, Ontario, CAN; Boston Celtics head coach Joe Mazzulla gestures as he speaks with game officials in the second half against the Toronto Raptors at Scotiabank Arena. Mandatory Credit: Dan Hamilton-Imagn Images Dan Hamilton-Imagn Images

Celtics' Joe Mazzulla Extension Set to Keep Him in Boston For Surprisingly Long Time

Originally posted on Boston Celtics on SI | By Jason Fray | Last updated Oct 28, 2025 11:00 AM ET

There are a few common themes and traits associated with any sports franchise.

Perhaps the most significant element is stability — namely in terms of collective management and team culture.

The Boston Celtics understand this premise considering their illustrious standing as one of the two most successful basketball entities in NBA history. Joe Mazzulla was handsomely rewarded for his coaching prowess over the last few years by inking a multi-year deal with the team this offseason.

Mazzulla's Long-Term Future with Boston is Ensured

The Celtics found their guy — and worked doggedly to get him locked up for the foreseeable future. It wasn't clear as to how many years Mazzulla got on his deal. However, longtime NBA reporter Marc Stein shed some light on the situation recently.

"Terms were not formally announced on Mazzulla's new pact beyond the Celtics terming it a multiyear contract extension, but there is a belief in coaching circles the new deal is a six-year pact, along the lines of the six-year pact that current Celtics president of basketball operations Brad Stevens initially signed to be Boston's coach when he left the college game in July 2013."

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Full story: https://t.co/hG52q2eI5i pic.twitter.com/HMTvsRm750
— Marc Stein (@TheSteinLine) October 21, 2025

Mazzulla has a .731 win percentage as a coach. This would technically make him the second-winningest coach of all-time. There' some context that needs to be employed in this situation. He's only coached in 249 total games. Comparatively speaking, he's got a ways to go before approaching the longevity of guys like Phil Jackson (1,640), Red Auerbach (1,419) and Pat Riley (1,904).

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There is something to be said about a guy that at only 37 years of age is already an NBA Champion and a coach that's led his team to two 60-win seasons out of three years at the helm.

We have signed Joe Mazzulla to a multi-year contract extension ☘️ pic.twitter.com/V82bnnSXte
— Boston Celtics (@celtics) August 8, 2025

The intensity with which Mazzulla coaches is a perfect fit in Boston. He's a true player's coach letting his guys work through mistakes and avoiding the micromanaging often associated with mismanagement.

As he gets older and garners more experience, his tactical acumen likely will continue to see an uptick. Boston has one of the best young coaches in the game locked up for the foreseeable future, and that facet alone should give the fan base enough confidence in the ownership group to continue to put a title-level product on the floor.