Otto Willumeit was born in 1905 in Sarrebourg, Lorraine which at the time was in Germany. He arrived in the United States in 1925 and became an American citizen in 1931. He returned to Germany in 1933 and received the degree of Doctor of Medicine in 1936 at the University of Bonn in Berlin.
He became Chicago Bund leader in 1938. In May 1944 he volunteered to surrender his American citizenship in government proceedings against him. At the time he was serving two consecutive sentences of five years for espionage and conspiracy to advise resistance to the draft.
Dr. Otto Willumeit died on December 30, 1989 in Holiday, Florida. He was married to Maria Willumeit also of Holiday, Florida who died in January 13, 1992.