Carter would continue to develop his game during the summer of 2015 where he led his AAU team, Georgia Stars, to a Nike Elite Youth Basketball League (EYBL) Peach Jam championship and was named Co-MVP alongside Jared Harper.

[3] after his sophomore season, Carter also earned the Georgia Region 6 AA Player of the Year and second-team Atlanta Tipoff Club All Metro-honors.

[4] He was named an honorable mention All-American by the Naismith Trophy, a first-team Junior All-American by MaxPreps, the Georgia Class AA Player of the year, the Atlanta/South Fulton Player of the Year, and a first-team all-state selection as a junior.

[6] As a senior, he averaged 22.7 points, 15.5 rebounds, and 5.8 blocks while leading the Knights to a Georgia class 3A state championship on March 9, 2017.

[7] Carter was named Georgia All-Classification Player of the Year, Gatorade Georgia Player of the Year, first-team All-America honors from the Naismith Trophy, second-team accolades from USA Today, and third-team recognition from MaxPreps.

Carter played in the Jordan Brand Classic, Nike Hoop Summit, and the McDonald's All-American Game, where he finished with 10 points, 5 rebounds, and 3 assists.

[8] Off of the court, Carter was named the Morgan Wootten National Player of the Year,[9][10] which goes to student-athletes who exemplify outstanding character, leadership, and academics.

[22] Against the Indiana Hoosiers, he had a double-double with 18 points and 12 rebounds despite being in foul trouble to lift Duke in a 91–81 win.

Following Duke's loss in the 2018 NCAA men's basketball tournament, Carter announced his intention to forgo his final three seasons of collegiate eligibility and declare for the 2018 NBA draft.

[39] On October 31, 2018, Carter scored a season high 25 points with eight rebounds, five assists, three blocks and three steals in a 107–108 overtime loss to the Denver Nuggets.

[41] On March 25, 2021, Carter and Otto Porter were traded to the Orlando Magic in exchange for Nikola Vučević and Al-Farouq Aminu.

[49] Carter played with the United States U17 team at the FIBA Under-17 Basketball World Cup, where he won gold.