President Barack Obama sipped stout and kissed babies as he landed in Ireland, marking the first of many planned events across Europe.
Along with first lady Michelle Obama, the president walked the thronged Main Street of quaint Moneygall.
The visit was met with thousands of well-wishers.
The sleepy village of 300 was the birthplace of Obama's great-great-great grandfather, Falmouth Kearney, a shoemaker who left in 1850 to begin a new life in the United States.
Irish Taoiseach (Prime Minister) Enda Kenny warned up the crowd with references to Ireland's affection for previous U.S. presidents, including John F. Kennedy and Bill Clinton.
But the 44th president is different, Kenny said, referring to Obama. He doesn't just speak about the American Dream. He is the American Dream.
The president joked with Kenny, returning the affection saying he was Barack Obama of the Moneygall Obamas, in a reference to the tiny town where his great-great-great grandfather was born.
He also told the crowd that he feels very much at home in Ireland, even more at home after that pint that I had during a stop at a pub in Moneygall where he met his eighth counsin, Henry Healy, 26, dubbed Henry the Eighth by townspeople.
For the United States, Ireland carries a blood link with us, Obama told Ireland's prime minister, Enda Kenny, in Dublin.
Obama will also visit Britain, France and Poland on a week-long trip in which he will discuss such issues as Afghanistan and Pakistan after the killing of Osama bin Laden, the world economy and the Arab spring uprisings.
Heard on the radio about the same time was a popular song, There's no one as Irish as Barack Obama.