From 2009 to 2015, he was Ambassador-at-Large heading the Office of Global Criminal Justice in the US State Department. During his tenure, he travelled more than 1.5 million miles to 87 countries to engage with victims, civil society organisations, investigators and prosecutors, and the leaders of governments and international bodies to further efforts to bring the perpetrators of mass atrocities to justice.
Ambassador Rapp was the Chief Prosecutor of the Special Court for Sierra Leone from 2007 to 2009, where he led the prosecution of former Liberian President Charles Taylor. From 2001 to 2007, he served as Senior Trial Attorney and Chief of Prosecutions at the United Nations International Criminal Tribunal for Rwanda, where he headed the trial team that achieved the first convictions in history of leaders of the mass media for the crime of direct and public incitement to commit genocide.
Before becoming an international prosecutor, he was the United States Attorney for the Northern District of Iowa from 1993 to 2001.
He received a BA degree from Harvard, a JD degree from Drake, and several honourary degrees from US universities in recognition of his work for international criminal justice.