He was the proconsul of the Achaia region.
Acts 18:12While Gallio was proconsul of Achaia, the Jews of one accord rose up against Paul and brought him before the tribunal,Acts 18:13saying, “This man is persuading people to worship God in ways contrary to the law.”Acts 18:14But when Paul was about to open his mouth, Gallio said to the Jews, “If it were a matter of some wrongdoing or serious crime, O Jews, I would have reason to listen to you.Acts 18:15But since it is a matter of questions about words and names and your own law, see to it yourselves. I refuse to be a judge of these things.”Acts 18:16And he drove them from the tribunal.Acts 18:17Then all the people seized Sosthenes, the ruler of the synagogue, and beat him in front of the tribunal. But Gallio paid no attention to any of this.