A Belorussian, Stepan Ivanovich Chernyak was born on 25 December 1899 in the village of Chernevichi, Borisovsky Uyezd, Minsk Governorate.

[1] During the Russian Civil War, Chernyak joined the Red Guard detachment commanded by Shevchenko in Orsha in November.

In early March at his request he was sent to the Separate Bashkir Brigade and appointed chief of the machine gun detachment of its 2nd Rifle Regiment.

In May with this regiment he took part in the suppression of the anti-Soviet uprising of Georgian Mensheviks in the areas of Tiflis and Batumi, after which the brigade guarded the Black Sea coast.

[1] From April 1932 Chernyak served as an instructor at the Training Center for the Preparation of Reserve Command Personnel of the 5th Corps District in Bobruisk.

In August 1939 he was appointed commander of the 136th Rifle Division, which as part of the 13th Army of the Northwestern Front fought in the Winter War.

After finishing its formation, from 23 August, the army covered the Soviet-Turkish border and the Black Sea coast as part of the Transcaucasus Front.

After recovering in April 1943 he was appointed deputy commander of the 5th Guards Rifle Corps, which as part of the 39th Army fought in the Rzhev-Vyazma, Dukhovshchina-Demidov, and Smolensk offensives, in the liberation of Verdino, Dukhovshchina, Rudnya and others.

In May 1945 for the breakthrough of the German defenses on the Oder and for successful fulfillment of objectives in the Berlin offensive he was awarded the Order of Kutuzov 2nd class.

From August 1947 he served as military commissar of Kalinin Oblast, and transferred to hold the same position in Krasnodar Krai in January 1954.