Having qualified as a solicitor in 1976, His Honour Judge Tom O’Donnell acted as a member of the Limerick Legal Aid Panel from 1980-1991 where he developed an extensive criminal defense practice, operating in the District Court, the Circuit Criminal Court, and the Central Criminal Court.

In 1991, he joined the firm of Holmes O’Malley Sexton and in 1998 was nominated to be a judge of the District Court. Five years later, in 2003, he was appointed to the District Court Rules Committee. He was subsequently appointed to the Digital Audio Recording Project Board in 2004 and in 2009 was instrumental in the introduction of video link facilities between Limerick District Court and Limerick Prison.

His Honour Judge Tom O’Donnell holds a diploma on the European Convention on Human Rights from University College Dublin, and a master’s degree in International Human Rights from the National University of Ireland, Galway. In 2007, he was further awarded a diploma on International Human Rights and Criminal Procedure by the International Bar Association.

He is the author of several articles in the Judicial Studies Institute Journal. In 2011, His Honour Judge Tom O’ Donnell was appointed a Judge of the Circuit Court and in 2012 was elected to the Interim Judicial Council.