Timothy McFadden was born in Dun Laoghaire in Ireland. After his education, he became deputy governor of the Curragh Prison in Co. Kildare, later rising to the governor (1975-1981). After that, he joined the Irish army. As an Irish Army officer, he served on UN peace-keeping tours in Lebanon, Namibia and the Golan Heights. In the early nineties, he left the Irish Army and started to work for the UN. In 1995, he was sent to Arusha with the task of setting up the detention unit for the International Criminal Tribunal for Rwanda (ICTR). After he completed that task, McFadden was transferred to The Hague, to the post of the commanding officer of the UN Detention Unit of the International Criminal Tribunal for the former Yugoslavia (ICTY).
When he arrived in The Hague in 1997, McFadden found only six accused in the Detention Unit, a modern facility which had 24 cells providing a reasonable level of comfort. Since then, the Detention Unit has been constantly expanding, with new accused and new cells being added, exceeding the number of 60 detainees.