[2] On his return, Piso addressed the Senate in his defence; Cicero replied with the coarse and exaggerated invective, a writing and/or oratory style or genre in classical times, known as In Pisonem.

[9] In the growing tension between Mark Antony and Octavianus, Piso played a role neutral to both parties, yet seeking some form of resolution between the two sides.

When the Senate opened the year 43 BC with debating over Cicero's motion to declare Antony an enemy of the state, Piso twice intervened over the legality of such an act, arguing for compromise.

[12] Still hoping for peace, Piso joined two consular Senators -- Lucius Marcius Philippus and Servius Sulpicius Rufus—in an embassy to Antony at his camp in Mutina later that month.

[14] According to Ronald Syme, Piso "united loyalty to Roman standards of conduct to a lively appreciation of the literature and philosophy of Hellas.

[16] The maxim fiat justitia ruat caelum ("let justice be done, though the heavens fall"), used by Lord Mansfield in Somerset's Case and in reversing the outlawry of John Wilkes, and in the alternate form fiat iustitia, et pereat mundus by Ferdinand of Habsburg, is sometimes attributed to Piso Caesoninus (more often to Gnaeus Calpurnius Piso), but this is disputed.