After the retirements of Bird and McHale, the departure of Parish, and the untimely deaths of 1986 draft pick Len Bias and star player Reggie Lewis, the Celtics struggled through the 1990s and much of the early 2000s.

After another period of rebuilding, the Celtics assembled a new "Big Three" around team captain Paul Pierce by acquiring Ray Allen and Kevin Garnett in the 2007 offseason.

[45] The move turned Boston fans against Brown, both because Kunnert and Washington were seen as key pieces of the team's future and because Auerbach publicly stated that he was not consulted about the trade.

[47] With public support strongly behind Auerbach, Brown sold the team to Harry Mangurian in 1979 rather than run the risk of losing his famed general manager.

Boston's hopes for 1988–89 faded when Bird underwent a procedure to remove bone spurs in his feet early in the season, and the Celtics won just 42 games before a first-round playoff defeat to the Pistons.

After thirteen NBA seasons and a gold medal at the Barcelona Olympics with the Dream Team, continued back trouble led Bird to retire in 1992.

[83] With McHale having retired after the Celtics' playoff loss to the Hornets, Boston's original Big 3 era came to an end in 1994 upon Robert Parish's signing with Charlotte.

Working alongside general manager Jan Volk, Carr selected University of North Carolina star Eric Montross with Boston's first-round pick in the 1994 NBA draft.

Things got worse in 1996–97 as the Celtics lost a franchise-record 67 games, setting an unwanted NBA record winning only once against other Atlantic Division teams and just fifteen victories overall.

In spite of the emergence of 1st-round draft pick Antoine Walker, Carr resigned after the season ended, while Rick Pitino was hired to join the franchise as the team's president, director of basketball operations, and head coach, reportedly on a $70 million ten-year contract.

With a promising start, upsetting the defending champions Chicago Bulls at home on opening night,[87] and hard play from the youngsters that led to leaderships in turnovers and steals, the team improved its victories from 15 to 36 despite many losing streaks.

After Boston lost to the Toronto Raptors on March 1, 2000, on a buzzer-beater by Vince Carter, Pitino delivered the memorable "walking through that door" speech, invoking Bird, McHale and Parish, which has been frequently cited over the years as a reality check for organizations wrestling with bygone glory.

[108] The Celtics then traded Ryan Gomes, Gerald Green, Al Jefferson, Theo Ratliff, Sebastian Telfair, and a first-round draft pick to the Timberwolves in exchange for superstar power forward Kevin Garnett.

The 2014–15 season had several roster moves, the most prominent being Rondo and rookie Dwight Powell traded to the Dallas Mavericks for center Brandan Wright, forward Jae Crowder, veteran point guard Jameer Nelson, and future picks.

[130] A total of 22 players spent time with the Celtics,[131] leading scorer and rebounder Sullinger suffered a season-ending left metatarsal stress fracture,[132] and the team was only tenth in the East with 28 games remaining.

[133] However, midseason acquisition Isaiah Thomas helped the team win 22 of their last 34 games, finishing the season with a 40–42 record, enough for the seventh seed in the Eastern Conference Playoffs.

[139] On August 22, 2017, the Celtics agreed to a deal that sent Isaiah Thomas, Jae Crowder, Ante Žižić, and the Brooklyn Nets' 2018 first-round draft pick to the Cleveland Cavaliers in exchange for Kyrie Irving.

On the team's opening night game in the first quarter against the Cavaliers, Hayward suffered a fractured tibia and dislocated ankle in his left leg,[142] causing him to be ruled out for the rest of the regular season.

Following a series of transactions, the team landed Romeo Langford with the 14th pick and also added Grant Williams, Carsen Edwards, and Tremont Waters (2020 G-league Rookie of the year).

[155] In the 2020 playoffs, the Celtics swept the Philadelphia 76ers in the first round, beat the Toronto Raptors in a seven-game series, and fell to the Miami Heat in the Eastern Conference Finals in six games.

[157] On June 2, 2021, the Celtics named head coach Brad Stevens as president of basketball operations replacing Danny Ainge after he announced his retirement.

In 2012, the year the Nets returned to New York in the borough of Brooklyn, there were indications that the rivalry might be rekindled when an altercation occurred on the court on November 28, resulting in the ejection of Rajon Rondo, Gerald Wallace, and Kris Humphries.

[183] The rivalry between the Celtics and the Detroit Pistons peaked in the 1980s, featuring players such as Larry Bird, Kevin McHale, Robert Parish, Isiah Thomas, Bill Laimbeer, Dennis Rodman, and Joe Dumars.

The two teams were highlighted by their star trios in Boston's Ray Allen, Kevin Garnett and Paul Pierce whereas Miami had LeBron James, Dwyane Wade and Chris Bosh.

[192] Forty-eight members of the Naismith Memorial Basketball Hall of Fame are connected to the Celtics,[193] and the franchise has retired 23 jersey numbers, more than any other American sports team.

Lucky's face and hands were both painted tan, while gold was included on the vest, bow tie and hat, as well as brown on the ball and shillelagh, and black on its pants and shoes.

The uniform, which is white with thick green stripes, features the full name in Futura Condensed stacked in front, and Red Auerbach's signature and quote "The Boston Celtics are not a basketball team.

The uniform is dark green with metallic gold and black accents, and has the "Celtics" wordmark inspired by the Slade's Bar & Grill restaurant once owned by Russell.

The Celtics have also worn a black band for reasons not directly related to the franchise, such as the Boston Marathon bombing in 2013 (later replaced with a dedicated memorial patch), and the death of Isaiah Thomas' younger sister during the 2017 NBA playoffs.

All Celtics games are heard on radio through Beasley Broadcast Group's WBZ-FM (98.5, otherwise branded as "The Sports Hub"), with play-by-play from Sean Grande and color commentary from Cedric Maxwell, a deal in place since the 2013–14 season.