On 29 February 2016, Dr Brammertz was appointed by the United Nations Security Council, as the Chief Prosecutor of the IRMCT.

In this role, he manages an international organisation of investigators, analysts and prosecutors, across Arusha, The Hague; and in regional offices in Kigali and Sarajevo.

Kofi Annan, then the UN Secretary-General, on 11 January 2006, appointed Brammertz head of the UN International Independent Investigation Commission into the murder of former Lebanese Prime Minister, Rafic Hariri.

On 1 January 2008, Brammertz resigned to succeed Carla Del Ponte as prosecutor for the International Criminal Tribunal for the former Yugoslavia.

In addition, he assisted the Council of Europe as an expert with a mandate to "set up a mechanism for evaluating and applying nationally international undertakings concerning the fight against organized crime".

Brammertz is a member of the Executive Committee of the International Association of Prosecutors,[6] and previously served as Chairman of the European Judicial Network.