Jayson Tatum complemented Rozier with 27 points, helping the Celtics beat the Hawks for the third straight time this season in a duel between the teams with the best and worst records in the Eastern Conference.
It was a good-news day all the way around for the Celtics, who reportedly agreed to terms with veteran free agent Greg Monroe on a one-year, $5 million deal hours before tip-off.
The Celtics were playing for a second consecutive game without All-Star guard Kyrie Irving, out with a bruised quad. Boston was also without Marcus Morris (hip), Marcus Smart (hand) and Shane Larkin (knee).
Taurean Prince paced the Hawks with a career-high 31 points.
Atlanta led 55-53 at halftime and hung within 80-72 before the Celtics ran away over the final 3:40 of the third period.
Rozier ignited a 14-3 spurt with a jumper and a 3-pointer. Then, after he and Tatum combined to make six free throws, Rozier capped the run with another 3-pointer, giving Boston a 94-75 lead headed into the final period.
Al Horford, who played his first nine seasons for the Hawks before leaving for a four-year, $113 million offer in free agency in 2016, contributed 17 points, six rebounds and seven assists to Boston's win.
Jaylen Brown had 19 points and Aron Baynes 11 for the Celtics, who were playing the middle game of a three-game homestand. They host Portland on Sunday.
Boston shot 50.6 percent from the field and 11-for-24 on 3s, with Rozier connecting on six of his eight 3-point attempts.
Rozier's previous career-high had been 23 points, set in November against Orlando.
Prince had 30 at Toronto in December for his previous career-best.
Dennis Schroder, hampered of late with a sore shoulder, added 25 points on 10-for-20 shooting for the Hawks, who were tipping off a three-day, two-game trip to Boston and New York.
Schroder, who entered the game with a team-leading 19.4 scoring average, had averaged just 12.8 points in his previous three games, shooting just 35 percent from the field and missing 14 of his 15 3-point attempts. He made one of his two 3-pointers against the Celtics.
Marco Belinelli (15) and Kent Bazemore (11) also scored in double figures for the Hawks, who have lost five of six.
--Field Level Media
Atlanta | Boston | |
Taurean Prince 31 | Scoring | Terry Rozier 31 |
Malcolm Delaney 5 | Assists | Al Horford 7 |
Taurean Prince 8 | Rebounds | Aron Baynes 8 |
Marco Belinelli 9 | Free Throws Made | Jayson Tatum 5 |
Taurean Prince 3 | Steals | Jayson Tatum 4 |
Kent Bazemore 1 | Blocks | Daniel Theis 2 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Atlanta | 110 | 42.5 | 11-31 | 31-34 | 21 | 36 | 4 | 6 | 12 |
Boston | 119 | 50.6 | 11-24 | 18-20 | 26 | 42 | 3 | 8 | 11 |