Niall is the co-founder of Irish America magazine as well as the founder of the Irish Voice Newspaper and Irishcentral.com and publishes Home and Away, a successful weekly freesheet. He was awarded an honorary doctorate by University College Dublin for his work on the Irish peace process which was a subject of a book Daring Diplomacy and a PBS Special An Irish Voice. He is also an adjunct professor at Columbia University journalism school.
He was a founder of the Irish Americans for Clinton campaign in 1991, supporting candidate Bill Clinton for president. He led an Irish American peace delegation to Northern Ireland after Clinton was elected and he acted as intermediary between Sinn Féin and the White House at a critical period in the peace process. He played a key role in securing a U.S. visa for Gerry Adams in February 1994. His role was featured in the book Daring Diplomacy by The Irish Times journalist Conor O’Clery and also in an RTÉ-PBS documentary entitled An Irish Voice.He has created numerous successful business networks through his publications including the Wall Street 50, Business 100, Hall of Fame, Legal 100, Silicon Valley 50 magazine in conjunction with the Irish Technology and Leadership Group, and the Science and Technology 50. He created the US Ireland Forum, a forerunner of the Diaspora forum held by the Irish government in 2009
Niall has written for The New York Times, The Guardian, The Irish Times and many other leading publications. He has spoken to groups involved in the Middle East peace process as well as the former Sri Lanka conflict about the importance of diaspora involvement in seeking solutions.
In 2002, his book Fire in the Morning, about Irish people at the World Trade Center during the September 11 attacks, reached number two on the Irish best seller list.
He was named among New York’s most influential people by New York magazine in their issue of May 15, 2006. He was featured on the “People You Should Know” segment of the Paula Zahn Now program on CNN in 2007. In January 2008, he was appointed an adjunct professor at Columbia University Graduate School of Journalism.