Within the University, he has been Head of the Department of Government, Mona, and a member, respectively, of the Boards of Graduate Studies and Undergraduate Studies. He has also been a Member of the Academic Board since 2002, and has been a member of the University Council of Jamaica as well as Chairman of the Board of Kingston College. While on secondment from the UWI, Professor Vasciannie has served, at different times, as the President of the University of Technology, Jamaica, and as Principal of the Norman Manley Law School.
In the international arena, Professor Vasciannie has been Jamaica's Ambassador to the United States of America and Permanent Representative to the Organization of American States (OAS), based in Washington, D.C.. In that latter capacity, he has been Chairman of the Permanent Council of the OAS as well as the Chairman of the Legal and Juridical Committee of the OAS. He has also represented Jamaica on the Inter-American Juridical Committee of the OAS, based in Rio de Janeiro, Brazil, and has chaired the Caribbean Conference on Maritime Delimitation.
Prior to taking up the post of Jamaican Ambassador to the USA, Professor Vasciannie served for five years as a member of the Geneva-based United Nations International Law Commission, working with other experts on the codification and progressive development of International Law.
Professor Vasciannie has also served, on a part-time basis, as a Deputy Solicitor General of Jamaica, working in the Attorney-General's Chambers. There, he was Director of the International Division of the Chambers, assisting in the provision of legal advice on a range of international law and other public law issues and taking part in litigation before the Judicial Committee of the Privy Council and the Inter-American Commission on Human Rights.
Professor Vasciannie holds the Jamaica national honour of Order of Distinction (Commander Class).