Leopold the Illustrious was the first Margrave of Austria and the progenitor of the Babenberg dynasty that ruled over Austria for many decades.

Like many people in early medieval times, Leopold had few details of his early life recorded. He is thought to have been born about 940. One of the first known mentions of him is as a grown man, a follower of then-Holy Roman Emperor Otto I. Known as Otto the Great, that emperor won a significant victory over the Magyars in 955 at the Battle of Lechfeld; after that victory, the emperor handed control of the Eastern March to a man named Burkhard and giving him the title of Margrave. Burhkard ran afoul of Otto the Great's son, Otto II, in 976 and lost his title and position. At that point, Leopold became Margrave of Austria.

Leopold set about securing his position, including taking the fortress at Melk, previously controlled by Burkhard. Leopold extended his realm to the east. He got his name from his successful efforts to organize the lands of which he had taken control. He was in Würzburg in 994, at a tournament, when he was struck in the eye by a wayward arrow. He later died of his injuries, on July 10.

Leopold had married Richardis of Sualafeldgau. They had had eight children, six of whom lived into adulthood: Henry, Ernest, Adalbert (985), Poppo (986), Hemma, and Christina. When Leopold died, his son Henry succeeded him as Margrave of Austria.