Tatum attended Chaminade College Preparatory School in Creve Coeur, Missouri
As a freshman, he averaged 13
3 points and 6
4 rebounds per game and was named 2013 Metro Catholic Conference Co-Player of the year
Prior to his senior year, Tatum made a commitment to Duke University over North Carolina, Kentucky and Saint Louis University
Tatum played in the 2014 FIBA Under-17 World Championship and the 2015 FIBA Under-19 World Championship, making the Eurobasket
com All-World Championship U-19 Second Team
Tatum was rated as a five-star recruit and considered one of the best prospects in the 2016 class
In his NBA debut for the Boston Celtics, Tatum recorded a double-double with 14 points and 10 rebounds as the team's starting power forward in a 102-99 loss to the Cleveland Cavaliers