Perry joined the United States national under-19 team at the 2019 FIBA Under-19 World Cup in Heraklion, Greece. On July 5, 2019, he led all scorers with 28 points and eight rebounds in a 95–80 quarterfinal win over Russia. In seven games, Perry averaged 13.1 points, 7.9 rebounds, and 1.4 steals per game, leading the United States to a gold medal. He was named tournament MVP and joined teammate Tyrese Haliburton on the All-Star Five.