Hizzoner drew jeers when he tried to joke about the Irish's fondness for booze in an impromptu speech to the American Irish Historical Society.
He noted he lived near the Irish society's Fifth Ave. home, and, on St. Patrick's Day, was used to seeing "a bunch of people that are totally inebriated hanging out the window waving," a transcript of the event shows.
His latest foot-in-mouth gaffe came while speaking at the society's St. Patrick's Day Parade book launch.
Dozens of society members - and the parade grand marshal, author Mary Higgins Clark - gathered to celebrate the debut of a book called "Celebrating 250 Years of the New York City St. Patrick's Day Parade."
Bloomberg was not on the program but was invited to make a few remarks, said society Executive Director Christopher Cahill.
After making his "inebriated" comment, Hizzoner seemed to realize he overstepped the bounds of decency.
"I know, that's a stereotype of the Irish," Bloomberg said to jeers. "Nevertheless, we Jews from around the corner think this."
The remark triggered a handful of boos from the crowd, and several Irish society members' eyes were not smiling that Bloomberg was trading in cultural stereotypes.
"It was ill-advised to make a statement like that," said John Dunleavy, chairman of the St. Patrick's Day Parade committee. "The remarks are highly, highly offensive to any Irish person.
"I don't think he would say a joke like that to any other ethnic group. It was totally uncalled for and unbecoming of the mayor," Dunleavy added.
Bloomberg did some bobbing and weaving Thursday when asked about the comments, which were first reported by IrishCentral.com.
"I certainly didn't mean anything that anybody should take offense to," Bloomberg said.
"I was talking about a party they have every year on St. Patrick's Day, where it's traditional to hang out the window and yell and scream, and it's all in good fun."
Later, he issued a mea culpa in a statement sent to reporters: "I apologize. I certainly did not mean to offend anybody."
The act of contrition was enough for City Council Speaker Christine Quinn, the city's highest-ranking Irish-American politician.
"Given the mayor's long history of support for the Irish community, his remarks last night were both surprising and inappropriate," Quinn said. "I am pleased to hear he has since apologized."