[2] Dhanapala was also a distinguished member of Constitutional Council of Sri Lanka and he was the Senior Special Advisor on Foreign Relations to President Maithripala Sirisena, and was Sri Lanka's official candidate for the post of Secretary-General of the United Nations, before withdrawing from the race on 29 September 2006.

The New York Times observed that Jayantha Dhanapala 'was a diplomat mostly unknown outside the arms-control world until he was elected to preside over this conference.'

Dhanapala was hand-picked by UN Secretary-General, Kofi Annan to take on the challenging job of Under Secretary General to re-establish the Department of Disarmament after the UN reforms of 1997, serving from 1998 to 2003.

He also broke new ground both in-house in taking managerial initiatives in gender mainstreaming and in work-life issues, as well as in the disarmament field by innovating the exchange of weapons for a development programme in Albania and other areas, and also in the cross-sectoral linking of disarmament with development, the environment and peace education programmes.

In the Security Council straw polls, he received the support from China, Congo, Ghana, Qatar and Tanzania, while Argentina, Denmark, France, Greece, Slovakia and the united Kingdom voted against Dhanapala with Japan, Peru, Russia and the United States remaining neutral.