A member of the Senate, he was appointed consul suffectus sometime prior to AD 183, most probably during the last years of the reign of Marcus Aurelius.
[2] Domitius Dexter was a key supporter of Severus’ bid for the imperial title after the murder of Pertinax.
In gratitude for his support, Severus appointed Domitius Dexter as praefectus urbi of Rome in June 193.
He held the post during an extended period when Severus was absent from Rome, having gone to the east to deal with his rival Pescennius Niger, reflecting the emperor's trust in his subordinate.
[3] Perhaps he was still in the office when he was elected consul prior alongside Lucius Valerius Messalla Thrasea Priscus in AD 196.