Mr Justice Iarfhlaith O'Neill comes to the High Court after 10 years at the senior Bar, during which his practice was largely commercial and personal injury.
He was born in Galway in 1950, but came to Dublin in 1961, where he attended Terenure College. He studied in UCD and the King's Inns before being called to the Bar in 1975.
The following year he married Jacinta Purcell and they have one daughter.
He was called to the Bar of England and Wales in 1986.
He has served on a number of boards and tribunals, including six years as vice-chairman of the Employment Appeals Tribunal, four on the Legal Aid Board and the past two as chairman of the Mining Board.
Although his practice has mainly been in the low-key, though lucrative, commercial and personal injury area, in 1997 he was involved in the C case, where he represented the parents of the 13-year-old Traveller girl who, while in the care of the Eastern Health Board, went to England for an abortion after being raped. Her parents sought to prevent this.
Widely liked, including by those who do not share his views, he was described by colleagues last night as "quiet", "competent", "a calm temperament", and "judicial".