Maciej Tomasiewicz is a graduate of the Karol Szymanowski Academy of Music in Katowice where he studied composition and theory of music as well as symphony and opera conducting (later completing a PhD) in the class of Szymon Bywalec. He then went on to attend the conducting master classes of Michael Dittrich, Gabriel Chmura, Jacek Kaspszyk, and Larry J. Livingston.
He is associated with the Archetti Chamber Orchestra of the city of Jaworzno, originally as a violinist, and between 2014 and 2021 as a conductor. He was head of the Polish Youth Symphony Orchestra in Bytom and the Karol Szymanowski Youth Symphony Orchestra in Katowice, both of which enjoyed considerable success under his guidance. He was awarded twice with a Conductor Resident scholarship from the Music and Dance Institute (IMiT). The artist has assisted to such esteemed conductors as Gabriel Chmura, Matthew Halls, Michail Jurowski, Jacek Kaspszyk, Michał Klauza, Christoph König, Alexander Liebreich, Jerzy Maksymiuk, Ludovic Morlot, Tadeusz Kozłowski, and Antoni Wit.
He has acted as assistant conductor with Polish National Radio Symphony Orchestra in Katowice, Jerzy Semkow Polish Sinfonia Iuventus Orchestra and the Grand Theatre of Łódź. He has conducted the Warsaw Philharmonic Orchestra, the Beethoven Academy Orchestra, the Polish Sinfonia Iuventus Orchestra, the Podlasie Opera and Philharmonic Orchestra of Białystok, the Polish Radio Orchestra in Warsaw, the Kalisz, Silesian, Świętokrzyskie, Zielona Góra Philharmonics as well as the New Music Orchestra, among others.
Since the 2022/2023 season, he has been the deputy music director at the Silesian Opera in Bytom, with which he has been associated for years and where he has conducted, inter alia, the premiere performances of the ballets (Scheherezade/Medea), shows (Sól Ziemi Czarnej), and operas: Giacomo Puccini’s Tosca, Pyotr Tchaikovsky’s The Nutcracker, Gaetano Donizetti’s L'elisir d'amore, Stanisław Moniuszko’s The Haunted Manor and Johann Strauss’ (Son) operetta Der Zigeunerbaron.
In the years 2019–2022, he was an assistant conductor to Andrzej Boreyko, Music & Artistic Director of the Warsaw Philharmonic.