Mirosław Janowski studied at the Fryderyk Chopin Academy of Music in Warsaw. From 1984 to 1995 he was assistant chorus master, then chorus master with the Teatr Wielki in Warsaw. In 1995 he became chorus director with the Roma Music Theatre in Warsaw, yet returned to the Polish National Opera in 1998.
In the course of his career he has prepared choruses for over 100 opening nights and 3,000 performances directed by the likes of Willy Decker, August Everding, Achim Freyer, Harry Kupfer, Keith Warner, Robert Wilson, Mariusz Treliński, Krzysztof Warlikowski, Mark Weiss, Michał Znaniecki and led by such conductors as José Cura, Enrique Diemecke, Placido Domingo, Patrick Fournillier, Valery Gergiev, Marc Minkowski, Alberto Zedda, Łukasz Borowicz, Gabriel Chmura, Jacek Kaspszyk, Kazimierz Kord, Wojciech Michniewski, Krzysztof Penderecki, Andrzej Straszyński, or Antoni Wit.
He conducted choruses in Aida, Boris Godunov, Carmen, The Queen of Spades, The Devils of Loudun, Don Carlos, Halka, King Roger, The Flying Dutchman, Madama Butterfly, Manon Lescaut, Maria Stuarda, Norma, Onegin, Paradise Lost, Guillaume Tell, The Magic Flute, Turandot, Tosca, Eros and Psyche, Goplana, Fidelio, Rigoletto, La Bohème, and more.
He was chorus master for the Ludvig van Beethoven Easter Festival concerts (Dvorak’s Stabat Mater and Brahms’s German Requiem), operettas, and musicals (e.g. West Side Story and Wonderful Town. He was the artistic director of the Warsaw-based Harfa Singing Society, conducted the Polish Radio Orchestra and Sinfonia Varsovia, and recorded collections of patriotic songs with the Media Choir for the Romuald Traugutt Philharmonics, Warsaw. Together with the Chorus of the Polish National Opera he performed at the ZAiKS Centenary Gala, Catholic University of Lublin Centenary Gala, Polish Independence Centenary Gala, Polish Olympic Committee Centenary Gala.
In September 2017 he took over as the chorus master for the Polish National Opera.