The Celtics are finalizing an agreement with Bucks associate head coach Charles Lee that will make him coach Joe Mazzulla’s top assistant, a league source confirmed Sunday.
Lee, 38, interviewed for head coaching jobs with the Bucks, Pistons, Suns, and Raptors in recent weeks. The last of those openings was filled Saturday, when Toronto hired Darko Rajakovic. Lee agreed to join the Celtics soon after.
Lee, a former Bucknell standout, played overseas and then worked briefly as an equity trader before becoming an assistant at his alma mater. In 2014, he joined coach Mike Budenholzer’s staff with the Hawks before following Budenholzer to Milwaukee in 2018.
He spent three seasons in Milwaukee alongside Celtics assistant Ben Sullivan, who is expected to leave Boston and reunite with former Celtics coach Ime Udoka in Houston. Last June, Lee was promoted to associate head coach of the Bucks.
He is the second high-profile addition to Mazzulla’s staff. Last week the team agreed to terms with 76ers assistant and former Celtics point guard Sam Cassell.
Boston’s coaching staff was shorthanded this past season. Top assistant Will Hardy was hired to coach the Jazz, Udoka was suspended and subsequently fired for having an inappropriate relationship with a subordinate team employee, and, in March, assistant Damon Stoudamire took over at Georgia Tech.
All of those openings were filled internally, with Mazzulla’s promotion from behind-the-bench assistant to the top role being the most prominent.