"The hope that I had that we'd start coming together in a serious way ... has been resisted," Obama told contributors gathered at the home of financier and former New Jersey Gov. Jon Corzine.
His intention, Obama said, is to make the 2012 campaign an "election in which we're not just talking slogans ... but we are looking soberly at the choices we face."
The president's outreach to donors came on a whirlwind day that began by taking on "birthers" who dispute he was born in the United States and producing his detailed birth certificate. He also flew home to Chicago to help pal and supporter Oprah Winfrey close out her syndicated talk show with a "big get" - an interview with him.
"Today was a fun day," Obama said as he entered his first fundraising event. "Nobody checked my ID at the door. But it was also a serious day because part of what happened this morning was me trying to remind the press and trying to remind both parties that what we do in politics is not a reality show. It's serious."
The three Democratic Party in New York fundraisers were scheduled across midtown Manhattan, including a dinner at The Waldorf-Astoria hotel. Obama was not due back at the White House until the wee hours of Thursday. He was expected to raise between $2 million and $3 million.
In Chicago, Obama and his wife, Michelle, took turns answering Winfrey's questions during a taped interview at her studio, her show's first interview with a sitting president and first lady. Winfrey has announced that she's ending her top-rated program on May 25 after a quarter-century on television.
The Obamas' interview is scheduled to air on Monday.
The show released one excerpt from the interview, an exchange over his decision to produce his Hawaii birth certificate. Laughing, he said: "Can I just say? I was there, so I knew that I knew I had been born. I remembered it."
Winfrey's relationship with the Obamas dates to their days in Chicago, and she lent her credibility and celebrity status to his 2008 presidential campaign with her first-ever political endorsement.
Corzine, who lost his political job in 2009 despite Obama's efforts to help him get re-elected, is a former chairman and CEO of Goldman Sachs. He has deep ties to the financial industry, which felt battered by Obama's rhetoric blaming the financial crisis on "fat cat" Wall Street bankers. The industry also chafed at the subsequent overhaul of financial regulations.
From Corzine's home, Obama was heading to Park Avenue for a dinner at The Waldorf-Astoria, followed by a concert-style event at the Town Hall theater primarily for his younger supporters and featuring The Roots, a hip-hop band from Philadelphia.
Since he became a candidate for re-election on April 4, Obama has embarked on an aggressive inaugural fundraising tour that included three events in Chicago on April 14 and six events spread over two days last week in Los Angeles and San Francisco.
Obama raised $750 million for the 2008 campaign and hopes to top that for his re-election.