Served as Secretary of the Department of Justice (DOJ), resolving renowned cases, including the prosecution of several prominent figures linked in the misuse of development funds, the electoral sabotage case versus former President Gloria Macapagal-Arroyo which led to her arrest, the dangerous raids of the prison cells for maximum security inmates, subsequently exposing and ending their luxurious lifestyle, and the overseeing of the Maguindanao massacre case.