"At a certain point I've just concluded that for me personally it is important for me to go ahead and affirm that I think same-sex couples should be able to get married," Obama told ABC's Robin Roberts in the interview at the White House.
The Bay Area has reacted to the first president now publicly and privately supporting marriage equality.
On the steps of San Francisco City Hall Wednesday afternoon state Lt. Gov. Gavin Newsom and Assembly Speaker John Perez, the first openly gay LGBT speaker of California, praised the president for coming out in support of marriage equality.
"He didn't need to do this," former San Francisco Mayor Newsom said. "We've got a president who puts everything on the line."
Recognizing Obama's upcoming re-election Newsom admitted there are consequences to speaking so strongly on a controversial issue, but noted the president's "political courage."
"It's rare to see this type of presidential leadership," the lieutenant governor said.
Newsom, who faced his own political backlash from his support of same-sex marriage eight years ago in San Francisco, said, "Even if you disagree with the president, you want strength of character."
In his decision to support the LGBT community Newsom believes Obama has shown that strength.
Newsom said he didn't think he would see a sitting president support gay rights during his lifetime -- let alone eight years after his efforts to legalize gay marriage.
"This country has evolved," Newsom said. "It's a generational thing," and not a Democratic or Republican issue.
Perez said as a gay man Wednesday was an emotional day.
"This sends a powerful message to young gays and lesbians," Perez said, who referred to marriage equality in the U.S. as a battle.
"Like the president's successful effort to repeal Don't Ask, Don't Tell, I believe today will be remembered as a major milestone in the LGBT movement," the speaker said.
DADT was repealed in December 2010 and now allows military personnel to openly express their sexuality while serving.
San Francisco's Castro District, known for its gay community and support of LGBT rights is celebrating Obama's support.
The San Francisco Lesbian Gay Bisexual Transgender Community Center at 1800 Market St. threw a party at the center with champagne and speakers including local activists and same-sex couples who have been involved in the fight for marriage.
The center's executive director Rebecca Rolfe acknowledged "we are really lucky to be here in San Francisco where there is widespread support for the LGBT community," and now "there's a groundswell of support" across the country.
Across the Bay Area and beyond, government officials have issued statements in response to the president's historic announcement.
San Francisco Mayor Ed Lee, who was appointed as interim mayor by former Mayor Newsom before Lee won the post in the November 2011 election, said in a statement that in San Francisco "we stand ready to begin marrying same sex couples, and we will take this hard fought fight all the way to the nation's highest court, if necessary."
City Attorney Dennis Herrera who has fought on the legal front of gay marriage said he was "delighted" with the president's announcement.
"President Obama now stands with San Francisco on the right side of history," Herrera said in a statement.
Herrera has worked to federally challenge Proposition 8, which was passed into California law in 2008 and eliminated the rights of same-sex couples hoping to marry.
-- Bay City News Service