Little is known about him, yet he was undoubtedly one of Józef Koffler's most distinguished and highly regarded students. In a letter to Slavko Osterc dated December 2, 1936, Koffler wrote:
[...] please keep an eye on my student Jakub Mund's works among the Polish submissions; though not fully developed, he is more modern than other Poles.
Thus, Koffler entrusted his friend with Mund's composition recommended by the Polish committee for the ISCM Festival jury in Paris. Unfortunately, subsequent correspondence with Osterc reveals that this work – Chamber Symphony – was never presented to the jury in late 1936, possibly due to conflicts between Koffler and the Polish section's authorities.
Initially working as a violinist at the Philharmonic, then as conductor of the Municipal Theaters' orchestra in Lwów, Mund succeeded Roman Palester as music director in 1934. From 1936, he also conducted the philharmonic orchestra. That year, one of Lwów's symphonic concerts featured his "quite successful composition" – Dance Suite (Alfred Plohn, 'VII. Concert - Mund-Dubiska', Chwila March 3, 1936, morning edition). In theater, he primarily conducted musical comedies and operettas, occasionally composing or arranging music for productions, including Euripides' Bacchae (1933) and Shakespeare's Coriolanus directed by Leon Schiller (1936). In 1938, a theatrical production titled Always Faithful: A Spectacle from Lwów's Past by Henryk Zbierzchowski was staged in Lwów, for which he also composed the accompanying music. In 1939, he composed the musical accompaniment for Wanda Dobaczewska's successful stage fairy tale Puss in Boots, directed by Szpakiewicz. During the Soviet occupation of Lwów, he conducted at the State Opera and Ballet Theater.
He likely perished at the Janowska concentration camp in Lviv (1941–1944). According to Filip Friedman (The Extermination of Lviv Jews, Łódź 1945), he played in the camp's prisoner orchestra under Leon Striks. Unconfirmed accounts suggest that, on Obersturmführer Wilhelm Rokita's orders, he composed 'death tango' (Tango fun toyt) - music played during prisoner selections and executions. Survivors recall its hypnotic, haunting melody.