Karłowicz was born in Vishneva (now part of Belarus) into a noble family, being part of the Clan of Ostoja. His father Jan was a Polish linguist, lexicographer and musician. As a child he studied the violin, for which instrument he later wrote his only concerto.
Karłowicz studied at Warsaw with Zygmunt Noskowski, Stanisław Barcewicz, Piotr Maszyński and Gustaw Roguski. He later studied in Berlin with Heinrich Urban, for whom he dedicated his Serenade for Strings which he composed and performed when he was still Urban's student. From 1906 to 1907 he studied conducting with Arthur Nikisch.
Karłowicz's music is of a late Romantic character. He was great admirer of Pyotr Ilyich Tchaikovsky whose Symphony No. 6 he praised. Tchaikovsky's influence can be heard in Karłowicz's earlier works, most notably the E minor symphony and the Violin Concerto. Like most of the late Romantics he also fell under the considerable influence of Richard Wagner, especially with Tristan und Isolde. Nevertheless he managed to develop an original musical language expressed in harmony and orchestration, the latter of which he mastered like few other composers and wrote some of the most colourful orchestral music ever found.
Karłowicz's music inhabits a primary place in the history of Polish music between Frédéric Chopin and Karol Szymanowski. Among his works are a Symphony in E minor (Rebirth, Op. 7), a Violin Concerto in A major (Op. 8), and several tone poems, which include Eternal Songs, Stanisław i Anna Oświecimowie, The Returning Waves and The White Dove. The Violin Concerto was written for and dedicated to his former teacher Stanisław Barcewicz, who premiered the work under Karłowicz's baton in Berlin on 21 March 1903 with the Berlin Philharmonic.
- Sala, Luca. European Fin-de-siècle and Polish Modernism. The Music of Mieczysław Karłowicz, Bologna, Ut Orpheus Edizioni, 2010.
- Anders, Henryk. Mieczysław Karłowicz. Życie i dokonania, Poznań, ABOS, 1998.
- Wightman, Alistair. Karłowicz, Young Poland and the Musical Fin-de-siècle, Aldershot, Ashgate, 1996; Polish translation by Ewa Gabryś, Karłowicz. Młoda Polska i muzyczny fin de siècle, Kraków, PWM, 1996 (Monografie Popularne).
- "Polish culture profiles: Mieczysław Karłowicz". Retrieved 2007-01-07.
- Free scores by Mieczysław Karłowicz at the International Music Score Library Project
- "Karłowicz's Stone - the last itinerary of Mieczyslaw Karłowicz (music, photos, videos, maps)". Retrieved 2009-02-23.
- Mieczysław Karłowicz at AllMusic
- Mieczysław Karłowicz at Find a Grave