[2][3][4][5] Educated as a lawyer, Deng was posted as Ambassador of Sudan to the United States, Canada, Denmark, Finland, Norway, and Sweden over the period 1972 to 1976.

After leaving Sudan's diplomatic service, he held several academic positions before becoming the United Nations' first Special Representative on the Human Rights of Internally Displaced Persons in 1992.

Under Sudanese presidents Ismail al-Azhari and Gaafar Nimeiry, Deng served as Human Rights Officer at the United Nations Secretariat (from 1967 to 1972).

[6] On 29 May 2007, United Nations Secretary-General Ban Ki-moon announced the appointment of Deng as the new Special Adviser for the Prevention of Genocide, a position he held until 17 July 2012 at the level of Under-Secretary General.

Before joining the Massachusetts Institute of Technology, Deng was a Distinguished Visiting Scholar at the John Kluge Center of the Library of Congress.

He has authored and edited 40 books in the fields of law, conflict resolution, internal displacement, human rights, anthropology, folklore, history and politics and has also written two novels on the theme of the crisis of national identity in Sudan.