On 12 December 1974, he was appointed by Pope Paul VI as auxiliary bishop of Osnabrück.
After graduation at the Carolinum High School in Osnabrück, he was drafted into military service.
Ordained a priest in 1952, he was a chaplain in Hamburg Winterhude 1955 to 1958, and completed a PhD in Rome.
After his retirement, Brandenburg lived first in Helsingborg, before returning to his home town of Osnabrück.
Sauerlandia Munster, a Catholic student fraternity that belongs to the Cartellverband der katholischen deutschen Studentenverbindungen.