His mother, a chief designer at one of the local plants, was interrogated during the Nazi-Romanian occupation of Odessa and killed after she refused to collaborate; her body was returned to Nikolai's grandfather "with traces of hanging".

Upon graduation he was supposed to enter the Military Institute of Foreign Languages, but it was closed in 1955 following Nikita Khrushchev's war reform.

[12] Around 1960 Gubenko arrived in Moscow and passed the entering exams for the acting department of VGIK, the course led by Sergei Gerasimov and Tamara Makarova which he finished in 1964.

[12] As a student he performed in one of the leading roles in the cult Soviet movie I Am Twenty (originally titled Ilyich's Gate) directed by Marlen Khutsiev.

Finished in 1962, it was screened at the Moscow Kremlin and greatly angered Nikita Khrushchev who compared it to an ideological diversion and criticized it for "ideas and norms of public and private life that are entirely unacceptable and alien to Soviet people".

His performance turned so powerful that Yuri Lyubimov who visited the play immediately made him an offer to join the Taganka Theatre, even though Gubenko had studied to be a film actor.

[12] He served there from 1964 until the end of the 1960s when he decided to dedicate himself to cinema and entered director's courses at VGIK, also led by Gerasimov and Makarova, which he finished in 1970.

[11] Fifteen leading roles were performed by real orphans — he had watched thousands of children from orphanages and boarding schools all over the country.

He was also offered the seat of the Minister of Culture of the USSR, becoming the first Soviet arts professional to hold a similar post since Anatoly Lunacharsky in 1917.