He was appointed duumvir navalis, with Gaius Matienus, by the Roman senate in 181 BCE, in order to equip a fleet against the Ligurians.
[1] He was praetor in 171 BCE, and received the command of a Roman fleet consisting of 40 quinqueremes in the Third Macedonian War against Perseus of Macedon.
[3] Even in the eyes of ancient writers, he, along with the consul Publius Licinius Crassus, behaved appallingly during the campaign, and was noted for his cruelty, allowing his troops to commit atrocities in Greek cities, even friendly ones.
[7][8] With the money he amassed from these activities, he continued a tradition of using plundered wealth to build public works (ex manubiis), and constructed an aqueduct at Antium, in the neighborhood of which Gallus had a private estate, and also adorned the shrine of Aesculapius with votive pictures.
[9] On Gallus's return to Rome in 170 BCE, Mictio, the leader of the Chalcidians, as well as a separate representative of the Athenians, appeared before the Roman senate and brought bitter complaints against him, in consequence of which he was accused by Gnaeus Aufidius and Manius Juventius Thalna [de] before the people, and condemned to pay a heavy fine of one million asses.