henry was the son of henry iii of brunswick-grubenhagen and margaret, a daughter of the duke jan i of żagań and scholastica of saxe-wittenberg. after his father's death in 1464, he succeeded him as prince of grubenhagen. since he was a minor, he was under the guardianship of his uncle, albert ii until he came of age in 1479. after 1479, he divided the principality with albert. albert received osterode castle and herzberg castle; henry received heldenburg castle. they ruled grubenhagen castle jointly.