"To hell with the recession! Let's dance!" shouted a leprechaun-dressed street entertainer in the vanguard of the parade. The 10-deep crowd roared with laughter at his lewd jig -- and, for an earsplitting hour featuring bands from India to Indiana, forgot its troubles.
But Ireland faces its sternest challenges in decades. Unemployment has soared above 10 percent, the government is increasing taxes and cutting spending to combat the worst budget deficit in Europe, and people are worried by rising emigration and renewed bloodshed.
From their pulpits, cardinals and bishops said the island's 4 million Catholics must reorder their priorities away from finances and toward family and community.
"Today I believe Patrick is calling the Irish to reconsider aspects of the culture and values upon which society has been built in recent years," Cardinal Sean Brady said in his annual sermon honoring Ireland's patron saint, who brought Christianity to the pagan Gaels in the 5th century.
"Like Patrick, can we not admit that we have been negligent in relegating God to the sidelines? Where is this preoccupation with personal wealth and success leading us? What has the breakup of family and community done to our happiness?" Brady asked.
He and other church leaders called for communities, in both the Irish Republic and the British territory of Northern Ireland, to isolate the gunmen who are spreading fear and dread. Irish Republican Army splinter groups killed three people this month in Northern Ireland and eight people have been gunned down in Dublin criminal feuds this year.
Catholic Archbishop Diarmuid Martin of Dublin said both parts of Ireland should "send an urgent and unambiguous message that as one community, north and south, without distinction of belief or of political allegiance, we are united against anyone who takes the path of violence."
But tensions in Northern Ireland forced authorities to cancel the parade in one town, Lurgan. Catholic youths in the town rioted over the weekend after the area's alleged senior IRA dissident was arrested on suspicion of killing two British soldiers.
Politicians from the Irish Catholic community canceled the parade for fear that the youths might use it to provoke more conflict with police and Protestants.
But Dublin's parade -- the climax of a six-day festival featuring fireworks, street theater and children's rides -- attracted an exceptional range of foreigners who, for the day at least, branded themselves Irish.
Children of all colors and accents painted their faces the green, white and orange of the Irish flag, donned Viking horns and leprechaun hats, and pressed shamrock tattoos on their cheeks.
But Dublin Lord Mayor Eibhlin Byrne warned that, as the economy sours, the city of 1.3 million faces a growing risk of racist violence. Many natives resent the 200,000-plus Eastern Europeans, Asians and Africans who settled in Ireland during its Celtic Tiger boom of 1994-2007.
"It's been a difficult -- for some devastating -- year. And now more than ever, we need to rebuild our communities and our sense of solidarity," Byrne said.
The mayor said Ireland's national holiday posed the question of "what it is to be Irish in the 21st century (and) how we blend our old and new cultures."