Mryj was born into a middle-class family in the Mogilev Governorate of the Russian Empire (nowadays the Mahilioŭ region in eastern Belarus).

After the Bolshevik revolution, he served in the Red Army[2] In 1921, Mryj became a teacher and also got involved in amateur theatre, ethnography and journalism.

Mryj was arrested by the Soviet secret police as a "member of an anti-Soviet counter-revolutionary organisation" in February 1934 and deported to Kazakhstan and then to Murmansk in the North of Russia.

In 1929, Mryj published his best-known work, a satirical novel "The Notes of Samson Samasuj" (Belarusian: Запіскі Самсона Самасуя, romanized: Zapiski Samsona Samasuja).

An inept official, he compensates his lack of competency by extraordinary activity in accelerating a cultural revolution in his district.