Krzysztof Marciniak has begun his vocal career in 1982 winning a competition organized by the Academy of Music in Łódź. In 1988 he graduated from the Vocal and Acting Faculty of the Academy under professor Adam Duliński.
He sang in premiere performances at the Grand Theater in Łódź already during his studies in the roles of: Damazy in The Haunted Manor by Stanisław Moniuszko, Bojomir in Zamek na Czorsztynie by Karol Kurpiński or in the title role in Der Schauspieldirektor Wolfgang Amadeus Mozart. In 1988 he started his cooperation with the Opera and Operetta in Szczecin and He was a principal soloist there until 1992. He came back to his home city the same year and became the principal tenor at Teatr Muzyczny in Łódź.
His most significant operetta roles include: Edwin (The Gypsy Princess), Sou-Chong (The Land of Smiles), Tassilo (Countess Maritza), Barinkay (Gypsy Baron), Alfred (Die Fledermaus), Camille (The Merry Widow) and other leading roles in operettas: The Blue Mask by Fred Raymond, Polish Blood by Oscar Nedbal, Popłoch wśród dziewcząt by Yuri Milutin and Viktoria und ihr Husar by Paul Ábrahám. In 1994 he was offered the part of Alfredo in Traviata by Giuseppe Verdi at Teatr Wielki in Poznań. After the premiere, he worked as a soloist in Poznań for a year. In 1995 he became the permanent soloist at the Grand Theater in Łódź and has worked there ever since.
He went on tours with the theaters he worked with and performed on the most significant musical stages in Europe: Berlin, Frankfurt, Stuttgart, Munich, Zurich, Salzburg, Brussells and Amsterdam. He took part in many musical festivals in Krynica, Kudowa and Ciechocinek. His operatic repertoire includes the roles of: Tamino (The Magic Flute), Ismaelle (Nabucco), Macduff/Malcolm (Macbeth), Dr Caius (Falstaff), Lensky (Eugene Onegin), Janek (Janek), Damazy (The Haunted Manor), Góral (Halka), the title role in Casanova by Ludomir Różycki and L'Abate di Chazeuil (Adriana Lecouvreur).