Wilhelm Sollmann was born on 2 April 1881 in Oberlind [de], Saxe-Meiningen (today a part of Sonneberg, Thuringia).

After the move to Coburg, Wilhelm attended the Casimirianum gymnasium from 1891 to 1897, when he had to leave due to the family's financial difficulties.

Working closely with Konrad Adenauer, whom he later described as "a personal friend and political enemy", Sollmann helped turn the Handelshochschule into the University of Cologne in 1919.

[1] In 1919, Sollmann also was a staff member of the German delegation to the Paris Peace Conference in Versailles, where he served as an expert on problems of the Rheinland occupation.

From 13 August 1923 until his resignation on 3 November, he served as Reichsminister des Innern (Reich Minister of the Interior) in the cabinets of Gustav Stresemann.

[citation needed] Having lost his German citizenship in 1936, in 1943 he was naturalized and changed his name to William Frederick Sollmann.

At the request of the American Friends Service Committee, a Quaker organization, Sollmann briefly visited occupied Germany in 1948, where he held speeches and radio addresses.

In 1949/50, the U.S. government consulted him on setting up a new German Civil Liberties Union (Bund für Bürgerrechte) and he worked for the Allied High Commission, but he had to return to the United States due to the onset of illness.

Sollmann was co-founder of the Carl Schurz-Gesellschaft, member of the Verbands deutscher Journalisten im Ausland and of the Legion for American Unity.