Henry was the second son of Duke Welf I of Bavaria (died 1101) from his marriage with Judith,[1] daughter of Count Baldwin IV of Flanders.

Through his marriage to Wulfhilde, daughter of Duke Magnus of Saxony,[1] about 1095, he acquired part of the Billung estates around Lüneburg (the nucleus of the later Welf duchy of Brunswick-Lüneburg).

He aspired to succeed his father-in-law as Saxon duke when Magnus died without male heirs in 1106, but was denied as the new king Henry V enfeoffed his follower Count Lothair of Supplinburg.

In 1116, he joined Emperor Henry V's second Italian campaign to seize the estates of late Margravine Matilda of Tuscany.

After Lothair won the tumultuous election, he imposed an Imperial ban on Frederick II, however, the king's forces were not able to conquer the Hohenstaufen territories in Swabia.