Prior to his appointment to the Supreme Court, Justice Leonen served as the University of the Philippines (UP) College of Law Dean in 2008 and as the chair of the government negotiating panel in talks with the Moro Islamic Liberation Front (MILF) in 2010. As chief negotiator from July 2010 to November 2012, he led the government in signing a Framework Agreement on the Bangsamoro with the MILF – a historic milestone in waging peace in Mindanao.
Leonen graduated fourth from the UP College of Law, passed the 1987 Bar Examinations and signed the roll in May 1988. Later on, he pursued his Master’s Degree in Law from Columbia University in New York. Prior to law school, Leonen graduated magna cum laude from the UP School of Economics and was a consistent valedictorian during his elementary and high school years.
A servant leader even in his youth, Justice Leonen served as the President of the Law Student Government during his stay at the UP College of Law. Striking a balance between the study of law and its application beyond the classroom walls, he passionately spoke of ideals while also focusing on realities happening outside the academe and how the two points could meet. During the height of Martial Law in February 1986, he was among the student leaders of the Law Liberation Forces that led UP Law students to EDSA. He led the UP Paralegal Volunteer Organization under the supervision of the Free Legal Assistance Group (FLAG), a group of human rights lawyers, which he also became a part of in 1987.
Even prior to passing the bar exam, Justice Leonen – a dedicated son of Baguio – co-founded the Legal Rights and Natural Resources Center Inc.-Kasama sa Kalikasan (LRCKSK-Friends of the Earth Philippines), a legal and policy research institution advocating the rights of long term upland communities composed of mostly farmers and indigenous peoples (IP).
Justice Leonen went on to become a member of the UP Law faculty, initially as a professional lecturer in Philippine Indigenous Law. In 2000, he was invited to act as UP System’s University General Counsel. In 2005, he became the first Vice-President for Legal Affairs of the UP System. He also became the Director of Legal Aid at the UP College of Law, and the Director of the Information and Publication Division of the UP Law Center.
It was in 2008 when he became the Dean of the UP College of Law. During his term, he built on the rich traditions of the college and at the same time, introduced changes and new experiences that allowed both faculty and students to become more engaged in critical discussions and attuned to current realities. As Dean, he allowed for intellectual discourse to flourish inside classrooms and beyond.
Today, aside from being an Associate Justice, he continues to be an inspiring mentor to those whom he works with, and a trusted friend to those who have the privilege of knowing him personally.