In 1472, Hermann made a bid to become Bishop of Hildesheim, but was forced to withdraw from the episcopal election after he failed to secure papal recognition.

In November 1475, Frederick III, Holy Roman Emperor appointed Hermann Stiftsgubernator.

Hermann assumed control of the administration of the Archdiocese of Cologne following the arrest of Archbishop Ruprecht of the Palatinate in 1478.

Hermann was allied with Maximilian I, Holy Roman Emperor and Pope Alexander VI.

He read mass and prayed the breviary regularly, and performed other episcopal liturgical acts.