His two younger brothers renounced their rights in order to become priests, which left Bernhard as sole ruler of Bernburg.

Along with his princely title, he also used the styles "Count of Askanien" and "Lord of Bernburg".

In 1328 Bernhard married Agnes (c. 1310 – 4 January 1338), daughter of Rudolph I, Elector of Saxony and Duke of Saxe-Wittenberg.

Her paternal grandmother and namesake Agnes of Habsburg was a daughter of Rudolph I, King of the Romans.

In c. 1343, Bernhard married for a third time to another Matilda (died after 28 June 1354), daughter of Magnus I, Duke of Brunswick-Göttingen.