Ballo competed at the 2019 FIBA Under-19 World Cup in Heraklion, Greece, missing the first two games due to visa issues. In five games, he averaged 17.6 points, 11.8 rebounds, and 3.8 blocks per game, leading Mali to a silver medal, the best performance by an African team at a global basketball tournament. Ballo was named to the All-Star Five with teammate Siriman Kanouté.