He was the son of Count Markwart of Eppenstein (d. 1076) and his wife Liutbirg of Plain, and he was the younger brother of Liutold of Eppenstein, who was enfeoffed with the Carinthian duchy after the deposition of the Zähringen duke Berthold by King Henry IV of Germany in 1077.
Both brothers had been loyal allies of the king during the fierce Investiture Controversy and the Walk to Canossa.
When the princes elected Rudolf of Rheinfelden anti-king, the Eppensteins ensured King Henry's safe passage back to Germany.
When Duke Liutold died childless in 1090, Henry IV vested him with Carinthia and the Veronese march, but transferred Carniola to the Patriarchate of Aquileia and Istria to Poppo of Weimar-Orlamümde.
In the course of the ongoing Investiture Controversy he entered into an armed conflict with Prince-Archbishop Conrad I of Salzburg in 1121.