Named as a brother of Max Gassmann, he served as a junior doctor in WWI.

A Fritz Gassmann, with medical training gained in Breslau and Paris followed by a career in radiology in Germany and, since 1923, in Worland, Wyoming, was considered for a post at the Israelitischen Kranken-Verpflegungs-Anstalt und Beerdigungs-Gesellschaft in Breslau in 1926. In the end, he remained in Worland until 1928.

Correspondence indicates that he styled himself "Frederick J Gassmann" in America and that he had a brother, also a doctor, in Liegnitz. His brother Martin's family cited him as a relative in Los Angeles when they sailed to the USA in 1938.