Severus Proculus was of noble descent, born in a wealthy and prominent family in Pompeiopolis, a city in the Roman province of Galatia.
He was the son of the Pontian Greek Senator and Peripatetic philosopher, Gnaeus Claudius Severus, and his second wife, the princess Annia Galeria Aurelia Faustina, daughter of Marcus Aurelius.
Through his mother, Severus Proculus was a relative to the ruling Nerva–Antonine dynasty of the Roman Empire and among his maternal aunts and uncles were the Empress Lucilla and Emperor Commodus.
By the time his maternal uncle was assassinated in December 192, Severus was one of Commodus' few remaining living male relatives, but he was completely ignored as a potential successor.
About 216, Severus Proculus may have made a political alliance with a Senator who was a member of the Pomponia gens and married his daughter to Pomponius Bassus.