He was educated first in Warsaw, later at the Royal Music Conservatoire in Leipzig (1906–10). He studied piano, theory, composition, and conducting. He began his career as assistant conductor and repetiteur at German opera houses. Later he conducted Scandinavian orchestras in Copenhagen (1914–16) and Oslo (Music Union Symphony and the Oslo Philharmonic, 1919–22). In 1922 Neumark settled in the Netherlands, where he led the summer concerts at Scheveningen and conducted Dutch orchestras, including the Concertgebouw.
during the ISCM festival in Amsterdam (on 9 June 1933). Neumark regularly gave concerts throughout Europe, and his frequent appearances in Poland included several performances in Lwów, always enthusiastically received. For example, in January 1935, Stefan Askenaze performed Ludwig van Beethoven's Piano Concerto in C major under his baton, and in March 1937, Neumark conducted the Lwów orchestra in works including Jan Maklakiewicz's Cello Concerto with Kazimierz Wiłkomirski as soloist. He also conducted the premiere performance of Koffler's First Symphony Op. 11 (1936) in Lwów.
Neumark lived in the United States during World War II. He returned to the Netherlands after the war and continued working as a conductor, also making guest appearances abroad. He was admitted to Dutch citizenship in 1951.