Dr. Riyad H. Mansour was born to a refugee family that lived in the city of Ramallah in the Occupied West Bank. In 1967, Dr. Mansour started his college education in the United States. Since his youth, he has always been involved in Palestinian politics and began his career in the Palestinian diplomatic service in 1983 at the Permanent Observer Mission of the Palestine Liberation Organization (PLO) to the United Nations (UN). He was appointed Ambassador and Permanent Observer of Palestine to the UN in 2005 and since 29 November 2012 he has been Ambassador and Permanent Observer to the State of Palestine to the UN. Dr. Mansour is also the non-resident Ambassador of the State of Palestine to Costa Rica and the Dominican Republic. Dr. Mansour was promoted on January 2019 with the rank of Minister of the State of Palestine and Chairman of the Group of 77 and China at the United Nations in New York.

Dr. Mansour joined the Permanent Observer Mission of the PLO to the UN, New York, in 1983 as Deputy Permanent Observer. He represented Palestine in several committees and bodies of the UN. In 1994, he joined the private sector accepting a position as Vice-President for Intram Investments, Inc. Orlando, Florida. There he was responsible for representing the company in governmental relationships, and was key strategist of land acquisition for developmental projects, in addition to other managerial responsibilities. In 2002, Dr. Mansour was also a consultant with Laventhal and Slaughter, P.A. and an adjunct Professor in the Political Science Department at the University of Central Florida.

Dr. Mansour, prior to joining the PLO in 1983, began his professional career as a Research Assistant at Youngstown State University, Youngstown, Ohio in 1972. He also held the post of Teaching Assistant at the University of Akron, Akron, Ohio, from 1973 to 1975, where he taught graduate courses in counseling and was responsible for counseling labs. From July 1977 to April 1983, he joined the Permanent Mission of the People’s Democratic Republic of Yemen to the UN in New York, as Research Adviser.
At the University of Akron, Akron, Ohio, Dr. Mansour obtained his Doctorate of Philosophy in Counseling in June 1977, with the minor area of concentration in Urban Studies with heavy emphasis on Research Methodologies. In June 1973, he obtained his Master of Science in Education Counseling from Youngstown State University, Youngstown, Ohio.

Dr. Mansour is fluent in oral and written Arabic and English. He also has published several studies and articles, particularly about the Palestinian community in the United States of America. He has lectured in many American Universities and has participated in numerous international conferences, symposia, seminars and panel debates as a representative of Palestine. He is also a member of senior official committees of the State of Palestine and the PLO.