His paternal grandparents were the Proconsul and Suffect Consul Gaius Julius Cornutus Tertullus and possibly Tertulla.
While his maternal grandparents were the Roman Senator and Proconsul Marcus Plancius Varus and Herodian Princess Julia.
Cornutus was of Roman, Jewish, Nabataean, Edomite, Greek, Armenian and Persian ancestry.
He was born and raised in Perga, the capital of the Roman province of Pamphylia.
Cornutus and his ancestors are highly praised as the benefactors of Perga and the inscription states how lawful, considerable and rewarding citizens they were.