He was a member of the NSDAP and member of the SA (SA Obersturmbannführer). He performed medical tests involving seawater on inmates at Dachau concentration camp. Beiglboeck was a defendant in the Nuremberg Doctor's Trial. He was convicted of war crimes and crimes against humanity, and sentenced to 15 years imprisonment. His sentence was commuted to 10 years and from 1952 - 1963 he served as the chief physician at Hospital of Buxtehude.