Doumbouya was selected with the 15th overall pick in the 2019 NBA Draft by the Pistons. The rookie appeared in 38 games, with 19 starts, for Detroit and also played in 16 G League games for the Grand Rapids Drive. Doumbouya made his NBA debut on Nov. 23 against the Bucks via a brief two minute appearance. The 19-year-old's first two double-digit scoring outings were also his first two double-doubles and occurred back-to-back. On Jan. 2 against the Clippers, he posted 10 points (4-11 FG, 0-4 3Pt, 2-3 FT), a career-best 11 rebounds and one steal in 27 minutes. Two nights later in a win over the Warriors, "Captain Cook" delivered 16 points (6-10 FG, 4-7 3Pt, 0-1 FT), 10 rebounds, two assists, two steals and one block. Doumbouya's first 20-point game occurred on Jan. 15 during a victory at Boston. In 28 minutes, he recorded a career-high 24 points (10-13 FG, 2-5 3Pt, 2-4 FT), two rebounds, one assist and one steal. Over his 38 NBA games, Doumbouya averaged 6.4 points and 3.1 rebounds in 19.8 minutes per game while shooting 39.0 percent from the field and 28.6 percent from three. Doumbouya played all but one of his G League games in November and December. Over his 16 G League appearances, he averaged 17.5 points, 5.3 rebounds, 1.3 assists and 1.0 steals in 27.0 minutes per contest. In his last G League game on Mar. 6, Doumbouya delivered 30 points, eight boards, two dimes and a steal during a win over the Red Claws.