In May 2010 Šimonović was appointed by the United Nations Secretary-General Ban Ki-moon as the Assistant Secretary-General for Human Rights. In October 2016, Šimonović has been appointed as the Secretary-General’s Special Adviser on the Responsibility to Protect.
In May 2010, Šimonović was appointed by the United Nations Secretary-General Ban Ki-moon as the Assistant Secretary-General for Human Rights. In October 2016, he was appointed as the Secretary-General’s Special Adviser on the Responsibility to Protect.