On December 22, 2019, Tatum scored a then career-high 39 points, along with 12 rebounds, in a 119–93 win over the Charlotte Hornets. He would exceed that career-high with 41 points against the New Orleans Pelicans in a 140–105 win on January 11, 2020. On January 30, Tatum was named an NBA All-Star for the first time in his career, being selected as an Eastern Conference reserve. On February 13, Tatum would again score 39 points, while playing 47 minutes and leading Boston to a 141–133 double overtime win over the Los Angeles Clippers. On February 23, he matched his career-high 41 points in a 114–112 loss to the Los Angeles Lakers. As the season was halted by the COVID-19 pandemic, Tatum would shoot 2–18 against the Milwaukee Bucks on July 31, but he would come back the next game scoring 34 points on 11–22 shooting in a 128–124 win over the Portland Trail Blazers on August 2. He was named to the All-NBA Third Team and his first selection of his career.