Bielschowsky worked with Ludwig Edinger (1855-1918) at the Senckenberg Pathology Institute in Frankfurt-am-Main where he learned histological staining techniques from Carl Weigert (1845-1904). From 1896-1904 he worked in psychiatrist Emanuel Mendel's (1839-1907) laboratory in Berlin. In 1904 joined Oskar Vogt (1870-1959) at the neurobiological laboratory at the University of Berlin, where he remained until 1933. Afterwards he worked at the psychiatric clinic at the University of Utrecht, and the Cajal Institute in Madrid.
Bielschowsky made many contributions concerning research of tuberous sclerosis, amaurotic idiocy, paralysis agitans, Huntington’s chorea and myotonia congenita. He is remembered for his pathological work with sclerosis and the use of an histological silver stain for impregnation of nerve fibers. The eponymous Bielschowsky sliver stain technique was an improvement on the method developed by Ramon y Cajal (1852-1934).