Education
He attended the University of Ulster where he obtained a Bachelor"s degree in Food Technology Management.
He attended the University of Ulster where he obtained a Bachelor"s degree in Food Technology Management.
He was a sports scholarship student at the university and is a former Irish international athlete. He is from Cloughaneely in County Donegal. Ó Domhnaill topped the poll on his first occasion running as the Fianna Fáil candidate in the Glenties local elecoral area.
He was an unsuccessful candidate at the Seanad election for the Industrial and Commercial Panel in 2007.
He was elected to Údarás na Gaeltachta board in 1999 and re-elected in 2005. He was nominated by the Taoiseach, Bertie Ahern to the Seanad on 3 August 2007.
He was the Fianna Fáil Seanad spokesperson on Lifelong Learning, Youth Work and School Transport in the 23rd Seanad. He is the Fianna Fáil Seanad spokesperson on Agriculture, Marine and Fisheries.
He was the Fianna Fáil candidate in the 2010 by-election in the Donegal South–West constituency, which was held on 25 November 2010.
He received 7,344 first preference votes (213%) and finished in third place on the final count. He was an unsuccessful candidate at the 2011 general election for Donegal South–West. He was elected to the Seanad on the Agricultural Panel in April 2011.
On 20 November 2012 the Standards in Public Office Commission announced a formal investigation into allegations relating to Ó Domhnaill"s travel and subsistence expenses claims.
On the 6 June 2013, the commission announced that it was postponing its investigation into Ó Domhnaill until a later date. In July 2013, during the Protection of Life During Pregnancy Bill 2013 Seanad debate, Ó Domhnaill claimed that allowing abortions in the case of foetal anomalies would deprive Ireland of future Special Olympics athletes.
He also remarked that Down Syndrome babies could be "left to die on sterilised trays".
He was a member of Donegal County Council for the Glenties area from 2004 to 2007.