The Irish American closest to the president, Deputy National Security Advisor Denis McDonough, 40, describes it as "a great blessing to work with Obama and for the American people.”

Denis McDonough is also chief of staff of the National Security Council (NSC). He works in a small office close by the president and is considered a key inner circle advisor.

In 1996, McDonough did part of his master’s thesis at Georgetown University on the Northern Troubles. “It was well into the Good Friday process and a very hopeful time,” he said in an interview with Lara Marlowe of The Irish Times.

He praises Gordon Brown and U.S. Secretary of State Hillary Clinton for their combined effort on the latest Northern Ireland agreement of February 5 on devolution of powers. He is direct in saying that the U.S. state department is in charge of Northern Ireland issues.

“Secretary Clinton did a great thing when she assumed the role of the envoy for herself. It underscores her commitment to it, and frankly it underscores the president’s commitment to it. They are in close touch on it.”

McDonough accompanied the first family to Hawaii last Christmas. He is six-feet-two, and frequently plays basketball with the president. He was first to inform him of the Haiti earthquake, after which Obama placed him in charge of post Earthquake planning and sent him to Haiti. He continues to play a key role in formulating foreign policy.

During the campaign he led a staff of over 300 policy advisers and was the key figure back then on Northern Ireland and the Irish American community. His grandparents emigrated from Galway; his mother's parents were O'Mahonys from Cork. He is also close to Irish Ambassador Michael Collins.

“When my mom and dad got married, they lived in south Boston, which is where the first six of my brothers were born. After that they moved to Minnesota, which is where the other five of us were born. So there’s 11 of us.”

He is deeply Catholic and two of his brothers are priests. Asked what being Irish in America is about he answered: “In a lot of ways, in the first instance it means being Catholic.”

McDonough’s wife, Karin, is of Swedish and Norwegian origin. “She grew up in Beverly, which is on the south side of Chicago, arguably the most Irish neighborhood in all of America.”

The McDonoughs have three children, Adeline, Liam and Teddy. Two were baptized Catholic, one an Anglican. The family attends both Catholic Mass and a Congregationalist church.

His time in Ireland has been limited to 10 days in 1991, when he was a student in Spain, and one week in 2000 when he and his wife lived in Germany. He says the president would love to visit Ireland, the president “keeps saying that he would very much like to . . . He is eager to go.”

Other key Irish Americans are also in the White House: vice-president Joe Biden is a Finnegan from Mayo on his mother’s side. Obama’s counter-terrorism adviser John Brennan’s father is from Roscommon. Samantha Power, who also works at the NSC, was born in Cork. But McDonough clearly has the president's ear.

“I provide my advice to him in private and I can tell you that there’s a lot of times when I provide advice that he ignores,” McDonough told The Irish Times. “The American people have an expectation that you will keep them safe.

“The president understands and takes that expectation very seriously. What we’re not going to do is stand up and brag about that fact. We do it every day. So we’ll just keep doing it . . . It’s the determined Irishman in me.”