The 2019-20 season marked Brown's third in the league and third with the Bucks. The 6-foot-5 wing averaged 5.1 points, a career-high 3.5 rebounds and 1.0 assist per game. During the fifth game of the season, Brown grabbed 11 rebounds in a win over the Magic. That was one short of his career-high 12 boards, which he accomplished Jan. 10 in a victory over the Kings. That 12-rebound effort also came with 11 points, representing Brown's one double-double. During the 10th game of the season in a win over the Thunder, Brown posted his first double-digit scoring effort of the campaign, recording 12 points, three rebounds, two steals and one assist. Three games later, he dished a season-high six assists in a win over the Bulls, also posting eight points, five rebounds and one steal. On Nov. 23, Brown grabbed 10 rebounds in a win over the Pistons while adding seven points, two assists and one steal. On Feb. 10 and Feb. 12, Brown posted two consecutive double-digit scoring efforts, dropping 11 points against the Kings first and 14 points against the Pacers second. He also combined for 14 rebounds, three assists, two steals and one block in those contests. Brown started the Bucks' final game before the COVID-19 hiatus, posting 16 points, six rebounds, three assists and one block. In the NBA bubble, during Milwaukee's second-to-last seeding game, the third-year pro posted a season-high 23 points while adding two rebounds, two assists and one steal. Brown appeared in one playoff game, grabbing one rebound.

Brown, in his second season in the NBA, appeared in 58 games for the Bucks (seven starts). He saw 17.8 minutes per game, averaging 6.4 points, 3.2 rebounds and 1.4 assists -- all career highs. He also shot 46.5 percent from the field, 36.1 percent from the field and 69.0 percent from the charity stripe, leading to a career-best 56.3 true-shooting percentage. Brown also posted a positive net rating (plus-1) for the first time in his career. On Mar. 31, during a one-point loss to the Hawks on the road, Brown had the best game of his season. He posted a career-high 27 points (10-22 FG, 5-10 3Pt, 2-2 FT), plus nine rebounds, three assists, three steals and one block across 33 minutes. It was his only 20-point game of the season and marked one of the three times he posted at least three steals. Across his seven starts, he averaged 13.9 points, 5.9 rebounds and 2.6 assists while totaling six steals and three blocks. Brown also appeared in 11 playoff games for Milwaukee, who went to the Eastern Conference Finals. His best performance was in Game 1 against the Pistons in the first round, a 35-point win in which Brown racked up 11 points (3-5 FG, 3-5 3Pt, 2-2 FT), seven assists, three rebounds, three steals and one block in 25 minutes.

Following four years at SMU, Brown was selected with the 46th overall pick in the 2017 NBA Draft. He appeared in 54 games for the Bucks, including four starts, and averaged 4.0 points and 2.6 rebounds in 14.4 minutes. Brown shot 40.0 percent from the field, 35.2 percent from three and 87.5 percent from the free-throw line. He also spent three games in the G League with the Wisconsin Herd. There, he averaged 21.7 points, 6.0 rebounds, 2.0 assists and 2.0 steals in 32.7 minutes. Arguably his best NBA performance took place Jan. 28 during a 14-point win over the Bulls. In 28 minutes, he posted 12 points (5-8 FG, 2-3 3Pt), six rebounds, two steals and one assist. It was one of his seven games with double-digit points. It was also one of Brown's four performances with at least one made three, one rebound, one assist and one steal. The Bucks finished the season 44-38 and lost in the first round of the playoffs to the Celtics. Brown played 13 total minutes in seven games, accumulating seven points, two rebounds and one steal.