Formerly serving as a monk, he was absolved of his religious vows by the pope in order to take the position.
His tenure was notable due to increased and constant conflict with the Archbishop of Cologne.
In 1300 he supported King Albert I of Germany against the Rhenish electors which further strengthened his position against the archbishop.
During his life he started foundations for monasteries and churches, including those in Beyenburg (now part of Wuppertal) and Gräfrath.
William and Irmgard are buried in the Berg family vault of the Altenberg Cathedral.