Maciej Tomasiewicz is a graduate of the 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 went on to attend the conducting master class of Michael Dittrich in Budapest, where he received Second Prize in a competition, as well as master classes taught by Gabriel Chmura, Jacek Kaspszyk, and Larry J. Livingston among others. He is associated with the Archetti Chamber Orchestra of the city of Jaworzno, originally as a violinist, and since 2014 as a conductor. In the years 2015–2019, he was head of the Polish Youth Symphony Orchestra in Bytom and the Karol Szymanowski Youth Symphony Orchestra in Katowice, which enjoyed considerable success under his guidance. He is the only conductor in the history of the Music and Dance Institute (IMiT) to be twice awarded a Conductor Resident scholarship.
The artist has worked under such esteemed conductors as Gabriel Chmura, Matthew Halls, Michail Jurowski, Jacek Kaspszyk, Michał Klauza, Christoph König, Alexander Liebreich, Ludovic Morlot, Tadeusz Kozłowski, and Antoni Wit. He has acted as assistant conductor with Polish National Radio Symphony Orchestra, 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 Kalisz, Silesian, Świętokrzyskie, Zielona Góra Philharmonics as well as the Silesian Chamber Orchestra and the New Music Orchestra, among others. He collaborates with the Silesian Opera, where he has conducted, inter alia, the premiere of the ballet Scheherezade/Medea to the music by Rimsky-Korsakov and Barber, as well as new productions of Tosca, The Nutcracker, Der Zigeunerbaron and The Haunted Manor. In Białystok he conducted such performances as Carmen and Turandot. In September 2019 he won a competition to serve as assistant conductor to Andrzej Boreyko, Music & Artistic Director of the Warsaw Philharmonic. In 2020, he was appointed artistic director of the Silesian Chamber Orchestra.