Henry's father, William IV, Duke of Brunswick-Lüneburg, retired in 1491, leaving government of Wolfenbüttel to his two sons, Henry, the elder, and Eric. In 1494, the brothers divided the territory between them, and Henry received the eastern part of the state, with the cities of Brunswick and Wolfenbüttel.
Starting in 1492, Henry laid siege to the City of Brunswick for a year and a half to enforce tax payments; the siege ended with a compromise. In 1501, Henry attacked Frisia, because the Frisians threatened the Archbishopric of Bremen, where Henry's son Christopher was coadjutor, but he had to abort the campaign.
In 1511, Henry, together with the other members of the House of Brunswick-Lüneburg, conquered the County of Hoya, which had refused to recognize Brunswick-Lüneburg as its liege lord. A second attack on Frisia in 1514 led to Henry's death; his head was shot off during the siege of Leerort Castle.
