Rozier appeared in 63 games for the Hornets during the 2019-20 season. He averaged per-game career highs in points (18.0), assists (4.1) and threes (2.7) across 34.3 minutes. He also averaged 4.4 rebounds, 1.0 steals and 0.2 blocks. Rozier shot a career-high 42.3 percent from the field, a career-high 40.7 percent from three and a career-high 87.4 percent from the charity stripe. Mar. 9 against the Hawks, Rozier established a new career-high 40 points. He shot 15-of-26 from the field, 8-of-13 from three and 2-of-3 from the free-throw line while also posting four rebounds, three assists and one steal in 44 minutes. Rozier's other single-game season highs were 10 rebounds, 10 assists, eight threes, four steals and two blocks. Rozier also had two double-doubles. Rozier had 25 games with at least 20 points, 31 games with at least five rebounds and 22 games with at least five assists. He had five games with at least three steals and eight games with at least one block.

Terry Rozier has proven to be a source of instant offense whenever given extended minutes. The 2018-19 season was no different. Rozier averaged 9.0 points, 3.9 rebounds, and 2.9 assists despite playing just 22.7 minutes per contest for a Boston roster that was much healthier than during the 2017-18 season. Celtic injuries in 2017-18 allowed Rozier to blossom and play 25.9 minutes per contest, so the 2018-19 drop in PT might have been frustrating for the young guard. "Scary Terry" topped the 20-point mark on five separate occasions, including 26 points in January against the Cavaliers and again versus the Clippers in March. Rozier continued to be a solid contributor from behind the arc, hitting 1.5 three point attempts per game. Rozier's scoring was helpful, but his rebounding from the point guard position really stood out. Rozier pocketed eight boards in two of Boston's first six contests and exploded for a season-high 11 boards against Atlanta on Jan. 19. Rozier's Celtics ended the season with a 43-39 record and swept Indiana in the first round of the playoffs. The Celtics then lost in to the Bucks in the second round of the playoffs.

Rozier appeared in 80 games for the Celtics during 2017-2018. Rozier would go on to start 16 times. He established career-highs across the board with 11.3 points, 4.7 rebounds and 2.9 assists per tilt. Scary Terry scored a career-high 33 points at Sacramento on Mar. 25, canning eight three-pointers in the process. Rozier attempted five treys per contest, hitting a career-best 38.1 percent from downtown. With Kyrie Irving sidelined for the playoffs, Rozier upped his game in impressive fashion. He recorded averages of 16.5 points, 5.3 rebounds and 5.7 assists during the postseason. Rozier played nearly 10 more minutes per game in the playoffs as he did during the regular season. He'd count at least 20 points in seven playoff games, as the Celtics advanced all the way to Game 7 of the Eastern Conference Finals before succumbing to LeBron James and the Cavaliers. And to cap off a productive campaign, Rozier would end up tied for tenth in the voting for both the NBA's Sixth Man of the Year and Most Improved Player.

In his second NBA season, Rozier appeared in 74 games off the bench for the Celtics, averaging 14.1 minutes per contest. He posted 5.5 points, 3.1 rebounds, 1.8 assists and 0.6 steals per game while shooting a then-career-best 36.7 percent from the field. Rozier scored in double-figures 16 times. He recorded a season-high 16 points against the Magic on Dec. 7, also adding five boards and two assists. In a loss to Portland on Jan. 21, Rozier put up 15 points, three rebounds and three assists. He grabbed a season-high 10 rebounds to go with 14 points and two assists against the 76ers on March 19. Versus Detroit on Nov. 30, Rozier handed out a season-high six assists. He swiped three steals against the Wizards on Jan. 24 and matched that total in a win over the Knicks on April 2. In the postseason, Rozier appeared in 17 of the Celtics' 18 games as they advanced to the Eastern Conference Finals. In Game 4 of the second-round series against Washington, Rozier established a new playoff-career-high with 16 points. In Game 5 of the Eastern Conference Finals, Rozier finished with 10 points, seven assists, four rebounds and two steals.

A rookie out of Louisville, Rozier appeared in 39 games for the Celtics, logging 1.8 points, 1.6 rebounds and 0.9 assists in 8.0 minutes. The 16th pick in the 2015 NBA Draft, Rozier made his NBA debut on Oct. 28 against the 76ers, finishing scoreless with one rebound in two minutes of play. He scored his first NBA points on Nov. 6 against Washington, when he hit two of eight field goals (1-3 3PT) to finish with five points and three assists in nearly 20 minutes of action. Rozier scored a season-high seven points on two occasions. Against Toronto on Mar. 18, Rozier had seven points, a season-high five assists and three rebounds. On Apr. 3 against the Lakers, Rozier had six points and a season-high seven rebounds. In the playoffs, Rozier saw action in five games against the Hawks in Round 1, averaging 4.8 points, 3.4 rebounds and 1.2 assists in 19.7 minutes per contest. Rozier also spent time with the Maine Red Claws of the G League. In 14 appearances, he posted averages of 19.4 points, 8.0 assists, 6.4 rebounds and 1.9 steals.