According to the Charter of the United Nations, the Secretary-General is appointed by the General Assembly on the recommendation of the Security Council. The Secretary-General is described by the Charter as the "chief administrative officer" of this organization; but his or her role includes not only administering the United Nation Secretariat, but also speaking out on global issues and using his or her good offices to mediate disputes.
UN Secretaries-General normally spend two terms in office; however sometimes they will serve only one if there is significant member state disapproval of their performance. Such is what happened to Boutros Boutros-Ghali.
The position of UN Secretary-General is supposed to rotate by geographic region; but that rule is often broken. Since Boutros Boutros-Ghali served only one term, his successor (Kofi Annan) had to come from Africa as well. But when Kofi Annan had finished his first term, the position should have gone to an Asian. But the member states have been very impressed with Kofi Annan's performance, and so they appointed him to a second term anyway.
- Trygve Lie (Norway), February 1946 to his resignation in November 1952.
- Dag Hammarskjöld (Sweden), April 1953 until his death in a plane crash in Congo September 1961;
- U Thant (Burma, now Myanmar), acting Secretary-General November 1961 and Secretary-General November 1962 to December 1971;
- Kurt Waldheim (Austria), January 1972 to December 1981;
- Javier Pérez de Cuéllar (Peru), January 1982 to December 1991;
- Boutros Boutros-Ghali (Egypt), January 1992 to December 1996.
- Kofi Annan (Ghana), January 1997 to present.