Úna Ní Raifertaigh practised as a barrister in the Irish courts between 1993 and 2016, first as a Junior Counsel and, after 2009, as a Senior Counsel. Her main speciality was criminal law, of which a large proportion was prosecution work. She was also involved in public law cases as well as a number of inquiries, including defence of a religious Congregation before a five-year Commission to Inquire into Child Abuse (2001-2006) and defence of the police Ombudsman (Garda Siochana Ombudsman Commission) in a judicial inquiry held in the autumn of 2016. She has represented Ireland on two occasions before the European Court of Human Rights in Strasbourg. Úna Ní Raifertaigh hwas been involved in a number of high-profile criminal trials relating to former bankers, arising out of the financial collapse of 2008. Prior to becoming a barrister, Una Ni Raifeartaigh was Reid Professor of Criminal Law in Trinity College Dublin (1991-5). She was appointed as a judge of the High Court in 2016.