Originally from Dublin, Ireland, Niall Mac Giollabhuí received his law degree from Trinity College in 1998 and qualified as a solicitor. 

During his time in Ireland, he represented at risk children in compelling the Irish State to recognize and protect their constitutional rights. He was also deeply involved in bringing a landmark constitutional case to force the Irish State to provide appropriate education for autistic children who had been victims of official neglect. He helped victims before the Residential Institutions Redress Board, which was set up in Ireland to compensate people who, as children, were neglected and abused mostly while in the care of Catholic religious orders. He fought for justice on behalf of women victims of the Dr. Michael Neary, an OB/GYN in a Catholic hospital, who was allowed for 25 years to carry out unnecessary caesarian hysterectomies on women without their consent.

In 2004, he led a team representing Ireland in the prestigious Philip C. Jessup International Law Moot Court Competition, the world's largest moot court competition, and was ranked amongst the competition’s top performers.

Niall Mac Giollabhuí shares Mike Dowd’s commitment to confronting and fighting injustice. He is dedicated to defending those wrongfully accused of crimes, to fighting for the dignity of victims of abuse, to standing up for those whose rights are threatened and providing a voice to those without.

He is admitted to practice in the State of New York and before the United States District Court for the Southern and Eastern Districts of New York.

A fluent Gaelic speaker, he is involved in a number of Irish-American organizations including the Irish American Bar Association of New York and the Brehon Law Society, of which he is the current Vice-President.