On June 18, 2015 Brunson was announced as a member of the 12-man 2015 USA Basketball Men's U19 World Cup Team for the 2015 FIBA Under-19 World Cup. Brunson earned MVP of the tournament, after leading the team with 5.6 assists and 2.1 steals for the tournament. He posted a game-high 30 points in the semi-finals against Greece, and he tallied a team-high 14 points including 6 in overtime as well as 7 assists, 5 rebounds and a steal in the gold medal game against Croatia. Brunson tied teammate Harry Giles, with a 14.0 average for the tournament. He dominated in the final two games. Based on this performance, he was recognized as the USA Basketball Male Athlete of the Year, on December 21, 2015.