From the late 1920s to early 1930s, Korniychuk was an active propagator of internationalism, strictly opposing the local National Communist movement in the Ukrainian literature, led by Mykola Khvylovy.

[7] In 1933, the first significant play by Korniychuk, Death of the Squadron, came out, endorsing the heroic tale of a Bolshevik Black Sea Fleet unit who chose to sink their ships so as not to be taken by the Germans (later revealed to be nothing more than a romantic revolutionary myth).

[7] Both Nikita Khrushchev and Lazar Kaganovich recommended the young author to Stalin and in 1938, the Soviet leader met the playwright at the Kremlin.

In 1939 came out what in retrospect is regarded by Russian critics as Korniychuk's strongest work, the 5-act drama Bogdan Khmelnitsky, telling the story of the 17th-century national movement in Ukraine which resulted in the country's unification with Russia.

His 1941 pro-collectivisation farcical comedy In the Steppes of Ukraine became popular with both the general public and Stalin himself, who in a personal letter informed the author: "Comrade Korneychuk.

[7] On 19 February 1943, the Ukrainian government newspaper Radyans'ka Ukraina in (briefly) liberated Kharkov published an article written by Korniychuk making it clear Stalin had no intention of giving up most of the territory gained by the Molotov–Ribbentrop pact after the war: it was promptly reprinted in Russian by Pravda the following day.

In 1951 the libretto for Konstantyn Dankevych's opera Bogdan Khmelnitsky he'd written with his wife Wanda Wasilewska met with harsh disapproval from Stalin, who demanded for a lot more of the Ukrainian people's fight against the "Polish oppression" to be shown.

In 1954 Korniychuk's play Wings, satirizing the style of local party officials' leadership, outraged some members of the USSR CP Central Committee.