West Belarus
In 1921, he moved into West Belarus in the Second Polish Republic. He served as principal of the Belarusian Gymnasium of Vilnia from 1924 to 1936. In the second half of the 1920s, he radically changed his political views. In 1924 he initiated the creation of a Polish-Belarusian Society that supported the Polish government. After the breakdown of the Society, Astroŭski cooperated with the Belarusian Communist Party (of Bolsheviks) and with the Communist Party of West Belarus, and managed the illegal komsomol cell in his gymnasium.