Pocar served in the Italian delegation to the UN General Assembly in New York and to the United Nations Commission on Human Rights in Geneva several times. He also served as an Italian delegate in the UN COPUOS (UN Committee on the Peaceful Uses of Outer Space) and its Legal Subcommittee.
In 1999, he was appointed as a judge to the International Criminal Tribunal for the Former Yugoslavia (ICTY), and was President of this tribunal from November 2005 to November 2008. He was also a member of the Appeals Chamber of the International Criminal Tribunal for Rwanda (ICTR) from 2000 until the ICTR's closure in 2015.
In 2017, Pocar was appointed Judge ad hoc of the International Court of Justice (ICJ) in the case between Ukraine and the Russian Federation. As of 2012 Pocar is President of the International Institute of Humanitarian Law (Sanremo, Italy). Pocar is a doctor honoris causa of the University of Antwerp and of the Kennedy University of Buenos Aires. In 2014 he was made Cavaliere di Gran Croce (Great Cross Knight, the highest Italian honor) by the President of the Italian Republic. He is a professor of International Law at the University of Milan.