Piso held several positions under Augustus and Tiberius. Ronald Syme infers that Piso was a military tribune in the Spanish campaigns of 26-25 BC. This accords with his known tenure as "triumvir monetalis" in 23 BC. Between that office and being appointed quaestor, which enabled him entry into the Roman Senate, Syme infers Piso was married. Syme fills the gap between those events and his consulate with various activities, such as accompanying his friend Claudius Nero in his Alpine campaign. At some date between 5 BC and AD 2 he was admitted to the College of Pontiffs.