He succeeded as duke of Lower Bavaria from 1310 until 1334 as co-regent of his brother Henry XIV and his cousin Henry XV. In 1322 he was in war with his co-regents, in 1331 Lower Bavaria was finally partitioned among them. Otto then governed Burghausen, Traunstein and several other Bavarian cities. Otto, who hated his brother made his cousin Emperor Louis IV, Holy Roman Emperor his contracted heir.
Otto IV married Richardis of Jülich. She was a daughter of Gerhard V of Jülich and Elisabeth of Brabant-Aarschot. They had one known child:
Albert of Wittelsbach. Born in 1332. Predeceased his father.