His career in imperial service is documented up to 18 May 247 from an inscription recovered at Fiumicino.

[1] Appointments he held up to that date include praefectus vehiculorum trium provinciarum Galliarum, procurator Alexandreae Pelusi and a third location (now lost), procurator portus utriusque Ostiae.

Valerian appointed him Praefectus of Roman Egypt, a position he held from possibly as early as 256 to 261.

[2] While the primary concern of the governor of Egypt was to safeguard the harvest and delivery of grain to the populace of Rome, he had other responsibilities which included resuming the persecution of Christians that had started under his predecessor Aurelius Appius Sabinus.

After a short struggle Aemilianus was defeated (before 30 March 262), captured, and later strangled in prison.