He was a son of Count Ulrich II (d. 1249) and the last Countess of Lebenau. He played a prominent rôle in the political life in Styria in the chaotic period between the death of Frederick II, the last Duke of Austria from the House of Babenberg in 1246 and the death of Ottokar II of Bohemia in 1278. Henry's role was much more prominent than that of his brothers Ulrich, Bernard and Siegfried.
In the dispute between Philip of Spanheim, who had been elected as Archbishop of Salzburg, and Count Meinhard I of Gorizia and Tyrol, Henry and his brother Bernard initially sided with Philip of Spanheim, in order to protect their fiefs in Carinthia, Styria and Salzburg. A deed of their alliance has survived, which was sealed on 1 June 1250 in Fohnsdorf; a number of vassals of the Pfannbergs are named as guarantors. Their stance in later years is less clear. Henry was bribed by King Bela IV of Hungary, who attempted to make his son Duke of Styria. In 1252, Ulrich sided with Ottokar, who was ruling Austria by then. Ulrich allegedly acted on behalf of all four brothers.
In 1253 Ottokar had settled himself in Styria. He appointed Henry as governor of Styria and returned to Bohemia. Bela IV then attacked Bohemia, and in the war that followed, Ottokar's father, King Wenceslaus I of Bohemia, was killed. The war was ended by the Treaty of Buda of 1254, in which Ottokar ceded Styria to Bela.
