"I'm honored and thankful to have my number retired with the Celtics," Garnett said in a statement obtained by Chris Forsberg of NBC Sports. "I will always have immense respect and appreciation for ownership, Danny Ainge, Doc Rivers, my past teammates, and Celtic Nation!"
Garnett accomplished plenty in his six-season stint in Boston. Upon his arrival via trade from the Minnesota Timberwolves in 2007, the then 31-year-old formed a formidable trio with franchise mainstay Paul Pierce and long-range sharpshooter Ray Allen.
The so-called "Big Three," alongside emerging talents like Rajon Rondo, Glen "Big Baby" Davis, Kendrick Perkins, and Tony Allen, quickly made good on their on-paper promise, defeating Kobe Bryant's Los Angeles Lakers in six games to capture the 2008 NBA title.
In addition to his lone NBA championship, Garnett was a one-time All-NBA selection, four-time All-Defensive team selection, five-time All-Star, and the Defensive Player of the Year in 2007-08 through his six seasons with the Celtics.
Garnett averaged 15.7 points, 8.3 rebounds, 2.7 assists, 1.2 steals, and one block per game while serving as the team's defensive backbone in 396 regular-season games from 2007-13. During Boston's title run in 2008, he upped those numbers to 20.4 points, 10.5 boards, 3.3 assists, 1.3 steals, and 1.1 blocks.
"Kevin gave everything he had to the Celtics in every practice, in every game, and his unique blend of energy, intelligence, and talent brought out the best in his teammates and coaches," said Ainge, the Celtics president of basketball operations.
To date, the Celtics have retired 22 players' numbers, including Bill Russell (No. 6), Bob Cousy (No. 14), John Havlicek (No. 17) Larry Bird (No. 33), and Pierce, whose No. 34 jersey was retired in 2018.
Garnett will almost certainly be announced as a first-ballot Hall of Famer when the 2020 inductees are announced at the NBA's All-Star Weekend in Chicago on Friday.