He was directly recruited as a singer by the Soviet authorities, his beard was shaved but he did not abdicate his curacy, and sent to study in preparation for the Bolshoi Theatre.

He became Joseph Stalin's favorite singer and most famous interpreter of the role of Ivan Susanin in the reworked "patriotic" Soviet version of the opera of that name, formerly and since better known as Mikhail Glinka's A Life for the Tsar.

In addition to Susanin, Mikhailov was a renowned interpreter of other bass and basso profondo roles in Russian opera: Pimen in Boris Godunov, the miller in Dargomyzhsky's Rusalka, Khan Konchak in Prince Igor, the Viking merchant in Sadko, Gremin in Eugene Onegin.

Mikhailov recorded many of his trademark arias under the conductors Nikolai Golovanov, Aleksandr Melik-Pashayev, Aleksander Orlov, and Samuil Samosud.

Among his recordings of songs, particularly well known with the pianists Nikolai Korolykov and Naum Walter are "O gentle autumn night" by Glinka, [Dargomyzhsky's "The Civil Servant", Viktor Kalinnikov's "On the Old Burial Mound", "The Blacksmith" by Yuri Sakhnovsky (1866–1930) and "The Seafarers" by Konstantin Vilboa (1817–1882).