He was suffect consul for February through July of the year 18, succeeding Germanicus as the colleague of Lucius Seius Tubero.
Syme suggests he may be the "Reg(ulus)" attested as praetor peregrinus in 2 BC, noting that "nothing would indicate a youthful consul.
"[4] Regulus appears once in the surviving pages of Tacitus' Annales, as one of three men who, in the year 20, defended Gnaeus Calpurnius Piso on charges related to the death from poison of Germanicus, after three other senators (Lucius Arruntius, Marcus Vinicius, and Asinius Gallus) declined for various reasons.
[5] Despite their efforts, and the support of the emperor Tiberius, the case went against Piso and he committed suicide before the Senate could hold a vote on the verdict.
Emperor Nero referred the matter to the Senate, who first tried to hand it off to the consuls, but in the end punished Pompeii with a 10-year ban on similar public gatherings, and having all of their guild associations dissolved.