[2] Between 26 and 24 BC, Antistius participated in the Cantabrian Wars, serving with the Emperor Augustus for most of the campaign as a legate.
Together with his colleague Gaius Firmius, they fought a difficult campaign to subdue the Gallaeci tribes of the more remote forested and mountainous parts of Gallaecia bordering the Atlantic Ocean, defeating them only after a series of severe battles,[3] though the details of this particular campaign remain unknown.
Due to the Emperor's illness, Antistius commanded the five legions of Rome at the Siege of Aracillum in 25 BC.
Antistius served with Augustus at Amaya, Bergida, and Monte Vindio, and after the successful campaign, went on to become the provincial governor (Proconsul) of Hispania Citerior.
Antistius began his political career as a triumvir monetalis in 16–15 BC.