| | C | Signed/Offer Sheet (The Boston Celtics signed C Neemias Queta to a rest-of-season contract.) |
| | SF | Recalled from Minors (The Boston Celtics recalled F Jordan Walsh from the minors.) |
| | PG | Recalled from Minors (The Boston Celtics recalled G Jaden Springer for the G League.) |
| | PG | Assigned to Minors (The Boston Celtics assigned G Jaden Springer to the minors.) |
| | SF | Assigned to Minors (The Boston Celtics assigned F Jordan Walsh to the minors.) |
| | PG | Traded (The Philadelphia 76ers traded G Jaden Springer to the Boston Celtics.) From |
| | SF | Traded (The Boston Celtics traded F Dalano Banton to the Portland Trail Blazers.) To |
| | PF | Traded (The Boston Celtics traded F Lamar Stevens to the Memphis Grizzlies.) To |
| | PF | Traded (The Memphis Grizzlies traded F-C Xavier Tillman Sr. to the Boston Celtics.) From |
| | PF | Signed/Offer Sheet (The Boston Celtics signed F Drew Peterson to a two-way contract.) |
| | PF | Waived (The Boston Celtics waived F-C Nathan Knight.) |
| | PG | Other Transaction (The Boston Celtics converted G JD Davison to a two-way contract. ) |
| | PF | Other Transaction (The Boston Celtics converted F-C Nathan Knight to a two-way contract. ) |
| | SG | Waived (The Boston Celtics waived G Jay Scrubb.) |
| | PF | Signed/Offer Sheet (The Boston Celtics signed F-C Nathan Knight.) |
| | PF | Waived (Boston Celtics waived Forward Wenyen Gabriel) |
| | SG | Waived (The Boston Celtics waived G DJ Steward.) |
| | PF | Signed/Offer Sheet (The Boston Celtics signed F Wenyen Gabriel.) |
| | PF | Waived (The Boston Celtics waived F Wenyen Gabriel.) |
| | PG | Traded (The Portland Trail Blazers traded G Jrue Holiday to the Boston Celtics.) From |
| | PF | Signed/Offer Sheet (The Boston Celtics signed F Wenyen Gabriel.) |
| | PG | Traded (The Boston Celtics traded G Malcolm Brogdon to the Portland Trail Blazers.) To |
| | C | Traded (The Boston Celtics traded C Robert Williams III to the Portland Trail Blazers.) To |
| | PF | Signed/Offer Sheet (The Boston Celtics signed F Lamar Stevens.) |
| | C | Signed/Offer Sheet (The Boston Celtics signed C Neemias Queta to a two-way contract. ) |
| | SF | Signed/Offer Sheet (The Boston Celtics signed G-F Svi Mykhailiuk.) |
| | SG | Signed/Offer Sheet (The Boston Celtics signed G DJ Steward to a training camp contract. ) |
| | SF | Waived (The Boston Celtics waived G Justin Champagnie.) |
| | SG | Signed/Offer Sheet (The Boston Celtics signed G Jay Scrubb to a two-way contract.) |
| | SF | Signed/Offer Sheet (The Boston Celtics signed F Dalano Banton.) |
| | C | Re-Signed (The Boston Celtics re-signed C Mfiondu Kabengele.) |
| | PG | Re-Signed (The Boston Celtics re-signed G JD Davison.) |
| | SF | Signed/Offer Sheet (The Boston Celtics signed F-G Oshae Brissett.) |
| | PG | Declared Free Agency (G JD Davison declared free agency.) |
| | C | Declared Free Agency (C Mfiondu Kabengele declared free agency.) |
| | PF | Declared Free Agency (F Blake Griffin declared free agency.) |
| | PF | Declared Free Agency (F Grant Williams declared free agency.) |
| | C | Traded (The Boston Celtics traded F-C Mike Muscala to the Washington Wizards.) To |
| | SF | Traded (The Boston Celtics traded F Danilo Gallinari to the Washington Wizards.) To |
| | PF | Traded (The Washington Wizards traded F-C Kristaps Porzingis to the Boston Celtics.) From |
| | PG | Traded (The Boston Celtics traded G Marcus Smart to the Memphis Grizzlies.) To |