Ernest was the fourth Margrave of Austria. He ruled for two decades in the 11th Century.

Ernest was born in 1027. Like many people in early medieval times, he had few details of his early life recorded. His father was the third Magrave of Austria, Adalbert, and his mother was Frozza Orseolo.

Adalbert had lent support to the Holy Roman Emperor Henry III, who was engaged in struggles against both Bohemia and Hungary. Adalbert died in 1055, and Ernest succeeded him as leader of Austria. He gained control of a few frontier territories, as previous margraves had done. He also made a name for himself fighting in support of Hungary's King Solomon, after he was deposed by his uncle Béla.

Ernest later fought with Holy Roman Emperor Henry IV at the Battle of Langensaiza, in 1075. This was an important part of the empire's putting down a Saxon rebellion.

Ernest died the day after that battle. He had married Adelaide of Ellenburg in 1060; their three children were Leopold, Justitia, and Adalbert. Adelaide died in 1071, and Ernest married again the following year, to Swanhild, with whom he had no children. When Ernest died, his son became Margrave Leopold II.