Hon. Peter Mohan Maithri Pieris is a distinguished legal professional with an illustrious career spanning several decades. He received his education at St. Joseph’s College and Royal College, Colombo, before qualifying as an Attorney-at-Law from Sri Lanka Law College. After being admitted to the Supreme Court of Sri Lanka in 1975 and the Supreme Court of England and Wales in 1978, he gained extensive legal training in the UK under the Commonwealth Training Scheme. Returning to Sri Lanka in 1981, he joined the Attorney-General’s Chambers, rising to the position of Senior State Counsel. During this period, he prosecuted high-profile criminal cases, represented the state in constitutional and administrative law matters, and received advanced training at institutions such as Harvard Law School and George Washington University.

Throughout his career, Justice Pieris held several prestigious positions, including President's Counsel in 2004, Attorney-General of Sri Lanka in 2008, and Chief Justice of the Supreme Court in 2013. He was involved in landmark judgments, reforms in legal education, and judicial processes, including electronic case filing and judicial mediation. His expertise extended beyond Sri Lanka, as he contributed to international arbitration cases and represented the country at significant international forums such as the United Nations Human Rights Council. In 2021, he was appointed Sri Lanka’s Permanent Representative to the United Nations, where he has been actively involved in key global issues, including disarmament, human rights, and peacekeeping missions.