Brissett was released by the Toronto Raptors just days before the start of the 2020-21 season and had to take the long route to make a return to the NBA. He earned a spot in the 2nd All G-League Team after averaging 18.6 points, 9.7 rebounds, 2.2 assists and 2.2 triples across 12 appearances for the Mad Ants before signing a 10-day deal with the Pacers. The former Syracuse standout made his Pacers debut April 6, tallying two points and one rebound across three minutes, but it wasn't until a second 10-day deal when he started to get into his own with Indiana. Brissett made his first career start April 19 and started every single game the rest of the way before the Pacers got eliminated in the Play-In Tournament. All things considered, Brissett made 18 starts across his 23 appearances and averaged 11.4 points, 5.5 rebounds, 0.9 assists, 0.9 steals and 0.9 blocks across 25.3 minutes per game. Brissett's best game of the season came against the Raptors on May 16, when he finished with 31 points and 10 rebounds. That was his lone 30-point performance and it was also one of his five double-doubles. Other season-high marks for the small forward were 13 rebounds, three assists (twice), three steals and five blocks. He also shot 48.3 percent from the field, 42.3 percent from three-point range and 76.9 percent from the free throw line.

After going unclaimed in the 2019 NBA Draft, Brissett signed with his hometown Raptors. He came off the bench for 19 appearances with the big club, adding another 28 games (21 starts) for the Raptors 905 in the G League. Brissett averaged 15.8 points, 6.9 rebounds and 1.0 steals for the 905. Working around ankle and knee injuries, he played 7.1 minutes per game for the Raptors, averaging 1.9 points and 1.4 rebounds. He also shot a noteworthy 80 percent from the free-throw line. In his best game of the year, Jan. 7 versus Portland, the rookie popped for 12 points on 5-of-9 shooting (including a pair of threes) along with six rebounds, an assist and a steal.