After his sophomore college season, Toppin declared for the 2020 NBA draft where he was selected with the eighth overall pick by the New York Knicks. Toppin was the winner of the 2022 NBA Slam Dunk Contest after being runner-up in the year prior.
Toppin redshirted his true freshman season after being ruled academically ineligible to play.[6] As a red-shirt freshman, Toppin led the Flyers with 14.4 points per game while averaging 5.6 rebounds per game and was named the Atlantic 10 Conference Rookie of the Week seven times.[7] At the end of the season, Toppin was named the Atlantic 10 Rookie of the Year and to the first team All-Atlantic 10, the first freshman to do so since Lamar Odom in 1999.[8][9] Following the end of the season he declared for the 2019 NBA draft, but did not hire an agent.[10] After working out for several NBA teams, Toppin opted to withdraw from the draft and return to Dayton.[11][12]
Entering his red-shirt sophomore season, Toppin was named to the preseason first team All-Atlantic 10 and to the Karl Malone, Lute Olson and Naismith Award watch lists.[13][14][15] Toppin was also named the 44th-best collegiate basketball player going into the 2019–20 season by CBS Sports and the 24th-best prospect for the 2020 NBA draft by ESPN.[16][17] He was named the Atlantic 10 Player of the Week for the first week of the season after scoring a career-high 29 points with 12 rebounds in the Flyers' season opening 86–81 win over Indiana State.[18] In late November 2019, Toppin led Dayton to second place at the 2019 Maui Invitational Tournament, averaging 22.3 points, 7.0 rebounds, 2.3 assists and 1.3 blocks over three games. He subsequently repeated as Atlantic 10 Player of the Week and was recognized as National Player of the Week by NBC Sports.[19][20] On December 30, Toppin scored a career-high 31 points in a 77–59 win over North Florida, including a school-record 10 dunks.[21] He was named to the midseason watchlist for the Wooden Award and was named the Midseason Player of the Year by The Athletic.[22][23]
On November 18, 2020, Toppin was selected with the eighth overall pick in the 2020 NBA draft by the New York Knicks.[37] On November 23, Toppin signed his rookie scale contract with the Knicks.[38][39]
On December 23, Toppin made his NBA debut, putting up nine points, three rebounds, and two blocks in 24 minutes, in a 107–121 loss to the Indiana Pacers.[40][41] Toppin missed 10 games due to injury sustained in his NBA debut,[42][43] and returned on January 13, 2021, in a 109–116 loss to the Brooklyn Nets.[44] As a rookie, he was invited to participate in the 2021 NBA Slam Dunk Contest and finished in 2nd place behind Anfernee Simons.[45] During the 2021 NBA Playoffs, Toppin recorded 13 points on an efficient 5-of-8 shooting from the field in a Game 4 loss to the Atlanta Hawks.[46]
The following season, in his sophomore year, Toppin was the winner of the 2022 NBA Slam Dunk Contest, beating Juan Toscano-Anderson in the final round.[47] On April 8, 2022, Toppin recorded a then-career-high 35 points and 2 steals, on 14-of-22 shooting from the field, and 6-of-9 from three, in a 114–92 win over the Washington Wizards.[48] On April 10, two days later, he recorded a career-high 42 points, along with 10 rebounds and a block, shooting 16-of-28 from the field, 6-of-14 from three and 4-of-4 from the free throw line, in a 105–94 win over the Toronto Raptors.[49]
During the final 5 games of the 2022–23 Knicks season, Toppin became a starter. On April 5, 2023, he tallied an impressive 32 points and 6 assists on 11-of-18 shooting from the field, 5-of-12 from three, and 5-of-5 from the free throw line in a win over the Indiana Pacers.[50] Four days later Toppin recorded 34 points, 7 rebounds, 5 assists, and 2 steals, on 13-of-23 shooting from the field, 5-of-10 on three, and 3-of-3 on free throws in a loss to his future team, the Indiana Pacers.[51] During the 2023 NBA Playoffs, Toppin became a starter in the second round, replacing injured Julius Randle, and recorded a then playoff career-high 18 points and 8 rebounds on 7-of-15 shooting along with 4 threes made, in a Game 1 loss to the eventual Eastern Conference ChampionsMiami Heat.[52]
Indiana Pacers (2023–present)
On July 7, 2023, Toppin was traded to the Indiana Pacers for two future second-round picks.[53] The deal came one day after brother Jacob Toppin signed with the Knicks. On the Pacers, Toppin joined Jalen Smith, Tyrese Haliburton, Aaron Nesmith and Jordan Nwora, all selected in the 2020 NBA draft. On October 25, as a starter, Toppin tallied 11 points, four rebounds, an assist, and a steal in his debut, defeating the Washington Wizards.[54] On November 6, Toppin recorded 19 points and two steals, on 6-of-11 shooting from the field and 6-of-6 on free throws, in a 41-point blowout win over rookie Victor Wembanyama and the San Antonio Spurs.[55] On November 14, he recorded a season-high 27 points, six rebounds, and a block, on 12-of-15 shooting, in a 2023 in-season tournament win over the Philadelphia 76ers.[56]
On January 26, 2024, Toppin put up a double-double with 23 points and 11 rebounds alongside a game-winning layup in a 133–131 win over the Phoenix Suns.[57] Toppin finished the 2023–24 season averaging career–highs as the main backup to Pascal Siakam. On May 2, he scored a playoff career-high 21 points in a 120–98 series-clinching victory against the Milwaukee Bucks in the first round.[58]
On July 6, 2024, Toppin re-signed with the Pacers to a four-year, $60 million contract.[59]