Mr Justice Sean Ryan has been appointed as a member of the Disclosures Tribunal.
The tribunal has been led by Judge Peter Charleton - who will return to the Supreme Court after finishing his report on the first module of the investigation concerning Maurice McCabe.
Judge Ryan will then take charge of the next phase of the tribunal, which deals with any other gardaí who feel they were targeted as a result of making a protected disclosure.
It is expected Judge Charleton's report will be completed in the Autumn, after which Judge Ryan will take over.
Judge Ryan retired as President of the Court of Appeal - a position he held since its establishment in 2014 - last March.
Prior to that, he was a Judge of the High Court. He also served as Chair of the Commission to Inquire into Child Abuse, which reported in 2009.
Minister for Justice Charlie Flanagan said: "I am very grateful to Mr Justice Ryan for agreeing to undertake this role.
"I believe that as a result of his vast judicial experience, he is very well qualified for this position and will ensure the continued effective running of the Tribunal.
"While Mr Justice Peter Charleton will not complete his work until the autumn, I would also like to take this opportunity to thank him for his sterling work since the establishment of the Tribunal and I look forward to his final report into these very important matters."
- Digital Desk