Olybrius was a member of the highly distinguished family of the Anicii which enjoyed excellent connections. One of Olybrius' ancestors had been Sextus Petronius Probus, a powerful ministerial figure during the reign of Valentinian I. Meanwhile Olybrius himself was married to Valentinian III's daughter Placidia the younger.
When in AD 465 Libius Severus died, Geiseric proposed Olybrius as a successor, hoping to increase his influence over the western empire. Though Leo, the emperor of the east, instead saw to it that in AD 467 his nominee, Anthemius, took the throne.
When alas the powerful 'Master of Soldiers' Ricimer fell out with Anthemius, Leo sent Olybrius to Italy to try and bring the two parties back together peaceably.
Leo realizing the danger of an emperor on the western throne who was a friend of the Vandals, sent a letter to Anthemius, urging him to see to it that Olybrius was assassinated. But Ricimer intercepted the message.
In any case Anthemius was most likely no longer in a situation to act. Shortly after, Rome fell and Anthemius was beheaded.
This left the way clear for Olybrius to succeed to the throne in March or April AD 472. Although Leo naturally refused to recognize his accession.
Only forty days after his conquest of Rome, Ricimer died a gruesome death, vomiting blood. He was succeeded as 'Master of Soldiers' by his nephew Gundobad.
But Olybrius was not to spend much time on the throne. Only five or six months after the death of Ricimer he too died from illness.