Mario Košik studied violin and conducting at the Bratislava Conservatory and at the Academy of Performing Arts in Bratislava. During this period he served as a leader of the second violins with Gustav Mahler Youth Orchestra under Claudio Abbado and French Youth Orchestra under Emmanuel Krivine. The experience of performing as an orchestra musician helped him in his later career as a conductor. His formal education was completed with a doctorate from the Academy of Performing Arts in Bratislava. His thesis focused on the social and psychological aspects of the relationship between the conductor and the orchestra.
His conducting career began in 1999 when he was appointed Principal
Conductor of Carlsbad Symphony Orchestra in Czech Republic — chosen from among 200 candidates. Throughout his tenure in Carlsbad he appeared as a guest conductor with major Czech and Slovak orchestras, including Slovak Philharmonic, Prague Symphony, Capella Istropolitana, Prague Chamber Philharmonic, Brno Philharmonic, Moravian Philharmonic in Olomouc and Janáček Philharmonic in Ostrava.
Between 2002 and 2006 he conducted new productions of four Slovak contemporary ballet pieces at the Slovak National Theatre.
Košik was appointed Principal Conductor of the Slovak Radio Symphony Orchestra in 2017. Besides conducting numerous studio recordings of works by Slovak modernist and contemporary composers, he also introduced many previously unperformed classical works into the repertory of the Slovak Radio Symphony (Nielsen, Roussel, Bernstein, Ives, Glass and Ginastera). In 2010 and 2014 he successfully toured Japan with the Slovak Radio Symphony.
Between 2009 and 2015 Košik was frequent guest of several Polish orchestras, including Polish National Radio Symphony in Warsaw, Gdańsk and Szczecin Philharmonic. In Kraków he successfully conducted Penderecki’s Cello Concerto in attendance of the composer. As a guest conductor he also appeared with Sofia in Bulgaria, Athens State Orchestra in Greece, Las Colinas Symphony in the USA, Jenaer Philarmonie in Germany, Orchestra Sinfonica di Roma in Italy, Jerusalem Symphony in Israel, Philharmonia in Krasnoyarsk in Russia, Orquesta de Ciudad Granada and Orquesta Municipal de Murcia in Spain. Recently he has performed with trio of South Korean orchestras — Seongnam Philharmonic, Daejeon Symphony and Kangnam Symphony. He also appeared in Japan as a guest conductor at the concerts of NHK Ensemble and Orchéstre philharmonique de Monte Carlo with famous Japanese pianist Fujiko Hemming.