The head of the NSPCC children's charity in Belfast will take charge of the Catholic Church in Ireland's child protection board.
Ian Elliott, who has led a major reform programme for Northern Ireland's child protection services, sees his role as "helping the Church to move beyond apology".
"Mistakes are tragic when not learned from, and it's imperative that - in future - we don't put the rights of anyone above the rights of the child," Mr Elliott said.
He said that he would embark on face-to-face meetings with churchmen and women and involved laity to support them in addressing the issue of child protection.
The implementation of the Church's child protection measures will be monitored by the National Board for Child Protection.
Pope Benedict XVI also noted last October that Irish bishops must deal effectively with problems caused by priests who sexually abuse children.
Bishop Colm O'Reilly, who chairs the One-Church Committee, welcomed the appointment.
He said that "the Church is extremely pleased to have secured a person of Ian's proven integrity, expertise and stature to head up this most important role at this moment in the Church's history, north and south".
Most recently, the Church said nearly 150 priests and members of other religious orders have been accused or suspected of abuse since 1940 in the Dublin archdiocese.
Fifteen thousand people have applied for compensation for abuse. Irish taxpayers are expected to pay compensation approaching $1bn (£0.5bn; 0.76bn euros).
