Joseph Arthur Mazzulla (born June 30, 1988) is an American professional basketball coach who is the head coach for the Boston Celtics of the National Basketball Association (NBA). He played college basketball for the West Virginia Mountaineers as a point guard.
Following his collegiate career, Mazzulla went undrafted in the 2011 NBA draft, and chose to pursue a career in coaching at the college level. He coached at Glenville State and Fairmont State as an assistant coach for three seasons each before being hired to be an assistant coach for the Maine Red Claws in 2016. In 2017, Mazzulla was rehired at Fairmont State, this time as their basketball program's head coach. After these stints of coaching at the collegiate level and in the NBA D-League, he joined the Celtics as an assistant coach in 2019.
In September 2022, Mazzulla was named the interim head coach of the Celtics after head coach Ime Udoka was suspended for the entire season. Mazzulla was named the full-time head coach in February 2023 after leading the team to a league-best 42–17 record at the NBA All-Star break. In his second season, Mazzulla led the Celtics to a league-best 64 wins and an NBA Championship. He currently holds the highest winning percentage of any coach in NBA history with over 200 games coached. Mazzulla is also the youngest head coach to win the NBA Finals since Bill Russell did so in 1969 as a player-coach and is the ninth-youngest head coach to win the Finals in NBA history.
Mazzulla has been noted in both NBA media and in general for his eccentric attitudes towards the game, his players, and the wins and losses he faces, leading some to nickname him Psycho Joe.
Joseph Mazzulla was born to Daniel Mazzulla Jr., an Italian American, and Latresa Mazzulla, an African American, on June 30, 1988, in Johnston, Rhode Island. He attended Bishop Hendricken High School in Rhode Island, making the all-state first team. Mazzulla won three state titles as a point guard at Bishop Hendricken, with his third as a senior on a last-second shot. As a senior, Mazzulla was injured in a car accident, sustaining no major injuries.
As a freshman at West Virginia, Mazzulla helped the team win the 2007 National Invitation Tournament under coach John Beilein.
In the 2008 NCAA tournament, Mazzulla posted 13 points, 11 rebounds, and eight assists in a second-round upset of Duke. He was forced to redshirt the 2008–09 season due to a shoulder injury against Ole Miss, as his growth plate never fused with his shoulder. Mazzulla was unsure if he would ever play again, but practiced for two hours a day and underwent surgery to make a comeback.
In April 2009, Mazzulla was arrested for domestic battery at a bar in Morgantown, West Virginia, and was suspended by coach Bob Huggins. Around this time, Mazzulla received a phone call from Mountaineer legend Jerry West. West criticized Mazzulla for failing to live up to expectations and pleaded with him not to waste his talents any longer. Mazzulla credits this call for helping to set him on the right path.
As a redshirt junior, Mazzulla was named a captain and helped West Virginia reach the 2010 Final Four, where the Mountaineers lost to eventual champion Duke. In the game prior, he scored a then-career-high 17 points in the Elite Eight upset of Kentucky.
As a senior, Mazzulla averaged 7.7 points and 3.8 rebounds per game.
In his collegiate career, Mazzulla recorded 700 points and 340 assists.
Shortly after graduating from college, Mazzulla was offered a coaching job at Nova Southeastern but turned it down to pursue professional playing opportunities. He joined Glenville State as an assistant in September 2011 after he was unable to find any professional playing opportunities.
In 2013, Mazzulla was hired as an assistant at Fairmont State under Jerrod Calhoun. During the 2016–17 season, Mazzulla served as an assistant for the Maine Red Claws of the NBA D-League.
Mazzulla was named head coach of Fairmont State in March 2017. During his second season, Mazzulla led the team to a 22–9 record and an appearance in the 2019 NCAA Division II tournament, where they lost in the first round to Mercyhurst, 63–60, in overtime.
On June 24, 2019, Mazzulla was hired as an assistant coach of the Boston Celtics. In 2022, he interviewed with the Utah Jazz for their head coaching vacancy, but the position ultimately went to fellow Celtics assistant coach Will Hardy.
On September 22, 2022, just days before the beginning of training camp, Mazzulla was named interim head coach for the Celtics after Ime Udoka was suspended for the entire 2022–23 season due to violating team policies. On December 1, Mazzulla was named Eastern Conference Coach of the Month for October and November after the Celtics began the season with a league-best 18–4 record.
On January 30, 2023, Mazzulla was named the head coach for Team Giannis for the 2023 NBA All-Star Game. A few weeks later on February 16, the Celtics officially named him the 19th head coach in franchise history and signed Mazzulla to a contract extension after he led the team to a league-best 42–17 record at the NBA All-Star break. In April, Mazzulla was named one of three finalists for NBA Coach of the Year. The Celtics entered the playoffs as the #2-seed in the Eastern Conference with a 57–25 record. They went on to beat the Atlanta Hawks in six games during the first round and the Philadelphia 76ers in seven games during the Eastern Conference Semifinals. However, the Celtics lost to the #8-seed Miami Heat during the Eastern Conference Finals in seven games, where Boston lost the first three games of the series. Despite losing the series, the Celtics became just the fourth team in league history to force a Game 7 after trailing 3–0 in a playoff series, and the first since the 2002–03 Portland Trail Blazers. During Game 7, star Jayson Tatum rolled his ankle less than a minute into the game and played through the injury, but was noticeably hindered for the rest of the game.
2023–24 season: First NBA Championship