at the World Trade Organization's Appellate Body Secretariat in Geneva. She was the only female member of the 1999 Preparatory Commission on Constitutional Reform where she headed the commission’s Steering Committee. In the same year, with Justice Jose Campos, Commissioner Haydee Yorac, and other professors from the UP College of Law, she co-founded Accesslaw, a corporation that provided the first annotated electronic research system in Philippine law. She also served as legal counsel for various government offices including the Office of the President, Office of the Solicitor General, Manila International Airport Authority, and the Department of Trade and Industry. She previously headed the Information and Public Division office of the UP Law Complex. She was also a lecturer at the Hague Academy of International Law. At the time of her appointment to the Supreme Court in 2010, Sereno was executive director of the Asian Institute of Management Policy Center. She was also the president of Accesslaw Inc., had taught at University of the Philippines College of Law for 19 years, and served as a consultant for the United Nations, World Bank, and US Agency for International Development. Sereno served as a co-counsel with Justice Florentino Feliciano on the Fraport case in Singapore, in which the Republic of the Philippines won the case. Supreme Court of the Philippines Associate justice (2010–2012) In August 2010, Sereno was appointed associate justice of the Supreme Court of the Philippines, its 169th member and the first appointee to the high court by President Benigno Aquino III. Sereno, the 13th woman appointed as justice of the Supreme Court, was the youngest appointee to the court since Manuel Moran in 1945 until Marvic Leonen surpassed her at the age of 49 in 2012. Chief justice (2012–2018) On August 24, 2012, President Aquino announced his appointment of Sereno as the new chief justice of the Supreme Court, replacing Renato Corona, who was removed from office in May 2012 after being convicted in an impeachment trial. Sereno voted against several of President Rodrigo Duterte's proposals, such as declaring martial law and burying Ferdinand Marcos in a cemetery reserved for national heroes. Sereno also took a stance on Duterte's Philippine Drug War when she called for due process for those included in Duterte's "drug list", a list of people alleged to be involved in the illegal drug trade. In a televised public speech in April 2018, Duterte addressed Sereno thus: