Bachelor with honors, University Peradeniya, Sri Lanka, 1961. Doctor of Letters (honorary). Master of Arts, American University, Washington, 1976.
Corporation executive in private sector, 1962—1965. Diplomatic appointments in China, United States of America, United Kingdom and India, 1965—1977. Director Non-Aligned Movement Division, Minister Foreign Affairs, 1978—1980.
Deputy high commissioner Sri Lankan High Commission, New Delhi, 1981—1983. Additional foreign secretary Minister Foreign Affairs, 1992—1995. Permanent representative United Nations, Geneva, 1984-1987.
Director United Nations Institute Disarmament Research, 1987-1992. Ambassador to the United States Washington, 1995—1997. Under-secretary-general disarmament affairs United Nations, New York City, 1998—2003.
Member Weapons of Mass Destruction Committee, Stockholm, 2003—2006. Secretary-general Secretariat for Coordinating the Peace Process in Sri Lanka, Colombo, 2004—2005. Senior advisory to President Government of Sri Lanka, since 2004.
President Review and Extension Conference of Treaty on Non-Proliferation of Nuclear Weapons, 1995. Representative United Nations to Conference on Disarmament. Member Canberra Commission, Australia.
Diplomat-in-residence Center for Non-Proliferation Studies, Monetary Institute of International Studies, California, United States.
Married Maureen Elhart. 2 children.