Executive Director of the Irish Penal Reform Trust Liam Herrick has been appointed as an adviser to President Michael D Higgins.
Mr Herrick will take up the three-year position in February.
He replaces President Higgins's former chief adviser Mary van Lieshout, who resigned from her post last November.
Media reports at the time suggested the resignation was due to a lack of access to Mr Higgins.
Mr Herrick has been at the helm of the Irish Penal Reform Trust since 2007. It is a non-governmental organisation dedicated to the reform of the penal system.
He has also lectured at a number of Irish universities and was appointed to be a member of the Irish Human Rights and Equality Commission.
Áras an Uachtaráin said Mr Herrick's salary will correspond to the first point of the principal officer scale.