Beefed-up security awaited the president's arrival at the Beverly Hilton hotel, where he arrived around 11:30 p.m. He was expected to stay at the hotel Thursday night and would leave from there sometime around 10 a.m. Friday. After Los Angeles, he planned to head to Reno, N.V.
Mr. Obama touched down at Los Angeles International Airport around 6:20 p.m. The main roads impacted by the visit until 10 p.m. Thursday were Laurel Canyon Boulevard, Ventura Boulevard, Mulholland Drive and Fryman Road.
Watch the exclusive interview of President Obama with ABC News' Robin Roberts
The fundraiser was expected to set a record for the most money raised for a single fundraising event. While stars paid $40,000 to attend the dinner, nearly two-thirds of the estimated $15 million raised for the event came from small online donations. Thousands of Democrats entered a raffle for as little as $3 for a chance to win one of two tickets to the fundraiser.
Mr. Obama's announcement on Wednesday ended years of what the president described as an "evolving" stance on the controversial issue. In an exclusive interview with ABC News' Robin Roberts, the president said his family helped change his mind.
"Malia and Sasha, it wouldn't dawn on them that somehow their friends' parents would be treated differently. It doesn't make sense to them, and frankly, that's the kind of thing that prompts a change in perspective," Mr. Obama said.
See a timeline of President Obama's evolution on same-sex marriage
Mr. Obama became the first U.S. president to openly support gay marriage. Despite his support, the president said it is still up to individual states to decide how to handle the issue. Thirty-one states have said no to same-sex marriage. California voters passed Proposition 8 in 2008, banning gay marriages. The courts recently overturned it, saying it is unconstitutional, but the legal fight continues.
The president's landmark announcement is being hailed by gay rights supporters.
"This is great. It's about time. The president of the United States has come forth and acknowleged that same-sex couples are entitled to equality for all, just like everybody else," said Lorri Jean, CEO of the Los Angeles Gay and Lesbian Center.
Read statements on President Obama affirming his support for gay marriage
Not everyone agrees with the president's view.
"Traditionally, marriage is between a man and a woman, and it should be that way," said Pasadena resident Al Coleman. "No need to change it."
Republican presidential candidate Mitt Romney addressed the controversial topic during a stop in Oklahoma on Wednesday.
"My view is that marriage itself is a relationship between a man and a woman, and that's my own preference. I know other people have differing views. This is a very tender and sensitive topic, as are many social issues, but I have the same view that I've had since running for office," said Romney.
Despite Mr. Obama's support of gay marriage, the issue that promises to dominate the election is the economy. The nation's highest ranking elected Republican, John Boehner, says he will stay focused on jobs and economy in the 2012 elections.
See celebrity reactions to President Obama's support of same-sex marriage
