Academic career Bersamin was in private practice from 1974 until 1986, when he was appointed a trial court judge in
Quezon City by President
Corazon Aquino. Bersamin was a professor at the
Ateneo de Manila Law School, the
University of the East College of Law, and the
University of Santo Tomas Faculty of Civil Law. He was special lecturer at the College of Law,
University of Cebu in 2006. He continues to lecture for the Philippine Judicial Academy.
Legal career In March 2003, Bersamin was elevated to the Court of Appeals by President
Gloria Macapagal Arroyo. In April 2009, Bersamin was elevated by President Arroyo to associate justice of the
Supreme Court of the Philippines. In July 2016, Bersamin was one of the Arroyo-appointed justices who voted to acquit Arroyo on the charges of plunder. Bersamin was the ponente when the Supreme Court allowed Juan Ponce Enrile to post bail, disregarding the Ombudsman's argument that the Philippine Constitution disallows the posting of bail by people charged with plunder. In October 2017, Bersamin voted to uphold the warrant of arrest against Senator
Leila de Lima. In December 2017, Bersamin voted to allow Duterte to extend for the third time
martial law in Mindanao. which led to the appointment of
Teresita Leonardo-de Castro as new
chief justice of the Philippines, replacing
Maria Lourdes Sereno. President
Rodrigo Duterte appointed Bersamin as the new chief justice on November 26, 2018, succeeding
Teresita de Castro.
GSIS chairperson On February 6, 2020, Bersamin was appointed by Duterte to be the chairperson of the
Government Service Insurance System (GSIS) and a member of the agency's board of trustees. He will serve the unexpired term of former GSIS president Jesus Clint Aranas, which ended on June 30, 2020.
Executive secretary Bersamin was appointed by President Bongbong Marcos as his
executive secretary, as confirmed by Press Secretary
Trixie Cruz-Angeles on September 27, 2022. The Supreme Court announced on February 5, 2025, that it issued writs of amparo and habeas data to the family of Felix Salaveria Jr., an environmental activist who was abducted in
Tabaco City, Albay, on August 28, 2024. The issuance orders respondents Executive Secretary Lucas Bersamin, the Armed Forces of the Philippines, and the Philippine National Police to present information they may have on Salaveria. Bersamin complied but he says Marcos declined his courtesy resignation. In September 2025 amid the
flood control projects scandal in the Philippines, DPWH Undersecretary Roberto Bernardo alleged in a sworn statement that the Office of the Executive Secretary got a 15% kickback from ₱2.85 billion in flood-control projects, to be given to Malacañang. Bersamin denied the allegations. On November 18, 2025, Malacañang announced the resignation of Bersamin to allow him to be subject to further investigation. Bersamin denied filing a courtesy resignation, and said that he got a call telling him that he "has to exit as executive secretary". House Deputy Minority Leader
Antonio Tinio (ACT party-list), House Assistant Minority Leader
Renee Co (Kabataan party-list), and Gabriela party-list Representative
Sarah Elago filed House Resolution 515 calling for a legislative probe on Bersamin, Representative Sandro Marcos, and other officials allegedly involved in the flood control corruption scandal. Bersamin denied being the person identified in the
Cabral files as "ES" (the abbreviation for "executive secretary"), who was allegedly assigned ₱8 billion in "allocable" funds in the 2025 national budget. ==Personal life==