Jayson Tatum is of mixed race and is a US citizen. Tatum also has two half-siblings.

In his NBA debut debut, Jayson achieved a double-double with 14 points and ten rebounds as the team’s starting power forward in a 102–99 defeat against the Cleveland Cavaliers. On October 24, 2017, Jayson set a season-best with 24 points in a victory over the New York Knicks.

Tatum was selected Rookie of the Month for December 2017 in the Eastern Conference. He was chosen to the NBA All-Rookie Team on May 22, 2018. (First Team).

Jayson set a career-best with 39 points and 12 rebounds against the Charlotte Hornets on December 22, 2019. On January 11, 2020, Jayson set a new career-best with 41 points against the New Orleans Pelicans in a 140–105 victory. 

Jayson was chosen as an NBA All-Star for the first time in his career on January 30 as an Eastern Conference reserve. Jayson and the Celtics agreed to a five-year, $195 million rookie maximum agreement on November 22, 2020. 

Jayson had 30 points, seven rebounds, and a game-winning three-pointer in a 122–121 win over the Milwaukee Bucks on the season’s first night, December 23, 2020.