He initially ruled Pomerania-Wolgast jointly with his elder brothers Barnim IV and Bogislaw V. He stood in their shadow and after 1368, he ruled his own part of the Duchy: the Land of Neustettin.

They supported Wartislaw V against Bogislaw V. The dispute degenerated into a civil war and Emperor Charles IV intervened.

He authorized a committee of arbitration, which included the Lübeck City Council.

On 25 May 1368, the dukes agreed on a preliminary division of Pomerania-Wolgast, in which Wartislaw V received the Land of Neustettin.

Wartislaw V was, according to the historian Martin Wehrmann (1861–1937), unmarried and reports to the contrary by some genealogists are incorrect.