He also served as counselor of the permanent mission of Côte d'Ivoire to the United Nations in New York from 1973 to 1975.

He later served as permanent representative of Côte d'Ivoire to the European office of the UN in Geneva and to UNIDO in Vienna, Austria from October 1975 to September 1978.

He also served as president of the Group of 77 in Geneva from 1977 to 1978 and was later named ambassador extraordinary and plenipotentiary to Switzerland.

In 1990 he became Minister of Foreign Affairs, and while in that position he served as President of the 49th Session of the United Nations General Assembly from 1994 to 1995.

[11] Essy is a member of the Global Leadership Foundation (chaired by FW de Klerk) that works to support democratic leadership, prevent and resolve conflict through mediation and promote good governance in the form of democratic institutions, open markets, human rights and the rule of law.