The post of Deputy Secretary-General was established by the General Assembly at the end of 1997 as part of the reform of the United Nations, to help manage Secretariat operations and to ensure coherence of activities and programmes. The purpose was also to elevate the Organization's profile and leadership in the economic and social spheres.
The General Assembly, decided to establish the post of Deputy Secretary-General as an integral part of the Office of the Secretary-General. The details were set out in Addendum 1 to the report of the Secretary-General and in the statement made by the Secretary-General on 4 November 1997 to the open-ended informal consultations of the General Assembly on United Nations reform. The item was entitled: measures and proposals, without prejudice to the mandate of the Secretary-General as provided by the Charter of the United Nations and, in accordance with the existing system of decision-making. Responsibilities delegated by the Secretary-General, to the Deputy Secretary-General included the following:
- To assist the Secretary-General in managing the operations of the Secretariat;
- To act for the Secretary-General at United Nations Headquarters in the absence of the Secretary-General and in other cases as may be decided by the Secretary-General;
- To support the Secretary-General in ensuring inter-sectoral and inter-institutional coherence of activities and programmes and to support the Secretary-General in elevating the profile and leadership of the United Nations in the economic and social spheres, including further efforts to strengthen the United Nations as a leading centre for development policy and development assistance;
- To represent the Secretary-General at conferences, official functions and ceremonial and other occasions as may be decided by the Secretary-General;
- To undertake such assignments as may be determined by the Secretary-General.
Louise Fréchette was the first Deputy Secretary-General of the United Nations. A national of Canada, she assumed her duties on 2 March 1998, after having been appointed by Secretary-General Kofi Annan. She remained at her post until 31 March 2006.
On 3 March 2006, Mark Malloch Brown was appointed as Deputy Secretary-General. He assumed his new functions on 1 April following the departure of his predecessor Louise Fréchette. He remained in his post until the end of December 2006.
Asha-Rose Migiro was the third Deputy Secretary-General to be appointed and took office on 1 February 2007. She remained in her post until the end of June 2012.
Jan Eliasson was the fourth Deputy Secretary-General to be appointed and took office on 1 July 2012 until the end of December 2016.