Balthasar led a successful resistance of the old Frisian aristocracy against the rise of the Cirksena family, which attempted to unite East Frisia under its rule from the late fifteenth century.
Allied to his close relations the Counts of Oldenburg and the Duke of Gelderland/Gelre, Balthasar Oomkens von Esens resisted the doubtful political power-grabbing attempted by the Cirksenas (which included a forged imperial document relating to the lordship of Harlingerland) and also championed the interests of the Catholic Church against the Reformation-minded allies of the Cirksenas.
He is generally remembered today as "Junker Balthasar" and in Esens (whose city rights he granted in 1527) there is a yearly festival in his honour.
There is a legend associated with Balthasar Oomkens von Esens which still finds expression in the city's coat of arms.
Breaking free of his chains, the bear climbed up one of the defensive towers, where his enraged roars attracted the attention of the besiegers.