O'Riain studied in University of Limerick and the National College of Art and Design where he came to prominence as a very successful street artist and student union president.
In late 2000 he travelled to Dublin to join W2W as a turnkey office fit out designer and design team manager. In two years he became familiar with all furniture and partitioning systems. However this experience was limited in the scope of application and he soon chose to move on.
In early 2003 he joined O’Riordan Staehli Architects in Cork to set up a commercial interior design practice within the architectural practice. From a standing start to today with a team of 8, the practice has become the most successful design team in the country with national and world awards complimented by a healthy turnover and profitability.
As part of the RORSA team, he has been recognised with the IDI Grande Prix in 2007 which is the country’s top Design award for the exceptional work on the Cork University Maternity Hospital.
The combined approach to the interior architecture of the Cliffs of Moher earned O'Riain and the Practice the World Commercial Interior Design award from the IFI.
O'Riain is dedicated to social and educational aspects and has lectured in NCAD, Carlow Institute of Technology, the University of Limerick, St Johns Central College and is external examiner for Cork Institute of Technology. O'Riain also create the first Cork Design Week in 2007 with a committee of volunteers as part of the IDI’s National Design Week