With his decades of work and his extensive publications, he has had a major influence on the research and communication of the History of the city of Bremen [de].
During the Second World War, he was first deployed in the Homeland Security, later in a technical department in the Soviet Union and in the West.
In 1953, he passed his first Staatsexamen and obtained his doctorate in Marburg with the historical work Entstehung und Anfänge der Stadt Bremen.
Until 1988, Schwarzwälder taught there as a full university professor with the following main subjects: Landesgeschichte [de], Nazism era and the Hanseatic League.
He gave many lectures and published numerous publications on the contemporary and cultural history of Bremen and Northwest Germany as well as the Hanseatic League.