Glaser studied piano, conducting, and composition at the Cologne Conservatory, and art history afterwards in Bonn. He finally continued his studies in composition with Paul Hindemith in Berlin, where he also took courses in psychology. From 1929 to 1931, he worked as a conductor at the Chemnitz Opera and went to Cologne in 1932 to conduct choirs. Persecuted by the Nazis due to his Jewish descent, he fled Germany for Paris in 1933. He subsequently moved to Lyngby, Denmark and lectured at the Frederiksbergs Volksmusikhochschule in Copenhagen, before escaping during the rescue of the Danish Jews to Sweden in 1943. In Sweden, he conducted the Södra Västmanlands Orkesterförbund from 1944 to 1959 and also directed the Västerås Musikskola, where his colleagues included Ivar Andrén and Gunnar Axén, until 1975. He also wrote music reviews and poems for the regional daily Vestmanlans Läns Tidning. He died in 2006 and was buried in the Jewish Cemetery in Stockholm.
Glaser left an extensive oeuvre which spanned many different genres. His tonal language clearly revealed the influence of Hindemith, but he also developed his individual style.