He played for the Russian under-19 team at the 2019 FIBA Under-19 World Cup in Heraklion, Greece. On 30 June 2019, Mikhailovskii recorded 20 points, 13 rebounds, and 12 assists in an 83–75 win over Greece. It was the first triple-double at the tournament since Dario Šarić in 2013.