Severus was of the gens Petronia. His father was Quintus Petronius Severus, born c. 70 AD, was a distinguished General and had a sister named Petronia Vara, born c. 75 AD.
Severus originated from the Petronia family. His father, Quintus Petronius Severus, who was born around 70 AD, held high military stature and had a sister, Petronia Vara, born around 75 AD.