He is said to have distinguished himself as commander of the garrison of an allied city besieged by barbarian pirates, and then made praetorian prefect by the emperor Valerian on the strength of this.
As praetorian prefect appears to have done useful work in restoring Antioch, the capital of the Roman East, after the devastation which had been inflicted by Shapur, the King of the Persians, in his invasion of 252.
However, he was overwhelmed by the circumstances with which he had to contend when Shapur invaded on a second occasion in 260 and seems to have shared in the defeat of Valerian at the Battle of Edessa and his subsequent captivity in Persia.
Successianus is first encountered, probably in 254, as the commander of the garrison of Pityus, a city in the Kingdom of Colchis on the eastern coast of the Black Sea in modern Georgia.
It is supposed that Successianus was with Valerian, still serving him as Praetorian Prefect when Shapur defeated him and took him captive near the city of Osrhoene Edessa in June(?)