After his father's death in 1439, he inherited the Duchy of Żagań with his younger brothers Rudolf, Wenceslaus and Jan II the Mad.
Shortly after his return, he had to face the claims of his brother Jan II who, dissatisfied with the part of the lands which had received, asked the review of the divisionary treaty.
In 1454 Rudolf was killed during the Thirteen Years' War in the Battle of Chojnice, fighting at the side of the Teutonic Knights.
After his death, Balthasar went to Prussia (Polish region), fighting on the Teutonic side and trying to gain a lieutenancy.
On his return, he found a complicated situation, as Jan II established himself as a Governor of the Duchy during his absence, and forced the Żagań states to paid homage to him.
In the following years Balthasar was involved in the Silesian political affairs, directly against George of Poděbrady, King of Bohemia.
After having unsuccessfully appealed to King George for the recovery of his domains, he went to Rome, where he obtained the support of Pope Pius II.