After the war Nikolai Grinko became an assistant director, and over time a leading actor of the theater, and worked extensively on the stage. From 1946 - actor of drama theaters in Zaporizhzhia and Uzhhorod. From 1955 - actor and artistic director of the Kyiv variety orchestra "Dnipro". From 1963 - actor of the A.P. Dovzhenko Film Studio. At his "home" studio named after A.P. Dovzhenko he was filmed very little, and was not offered a single leading role. His talent was used more fruitfully by Moscow film studios, where he played his best and largest roles.

Honored Artist of the Ukrainian SSR (1969). People's Artist of the Ukrainian SSR (1973). Nikolai Grinko had a distinctive high voice, so in some films his roles were dubbed by other actors. Nikolai Grigoryevich died in Kyiv on 10 April 1989 of leukemia. The actor is buried at the Baikove Cemetery in Kyiv. Chapter 17 of Leonid Filatov's series "To Be Remembered" is devoted to the actor's life and work.