[1] Shchetinkin was born to a peasant family in 1884 in Chufilovo Village, present day Spas-Klepiki, Ryazan Oblast.

After the fall of Achinsk to White Russian forces, Shchetinkin went underground and directed the formation of partisan detachments.

Shchetinkin served in 1920 as a member of the Extraordinary Revolutionary Tribunal that interrogated and ordered the execution of White Russian Commander Alexander Kolchak and Prime Minister Viktor Pepelyayev in Irkutsk.

In 1921 Shchetinkin commanded the Red Army expeditionary detachment that, along with Mongolian partisans under Damdin Sükhbaatar, invaded newly independent Mongolia to defeat the anti-Bolshevik Lieutenant General Baron Roman von Ungern-Sternberg whose Asiatic Cavalry Division had wrested control of Outer Mongolia from occupying Chinese forces earlier that year.

[3] In 1922 he studied military-academic courses and became chief of the regional department of the Joint State Political Directorate (OGPU) plenipotentiary representative in Siberia.