The controversy had threatened to detract from the party's drive to draw a sharp contrast at their Charlotte, North Carolina convention with Republican nominee Mitt Romney on the eve of Obama's nominating speech on Thursday.
Delegates had faced a torrent of Republican criticism and some from within the party after dropping pro-forma references to God and the party's support for Jerusalem being recognized as the capital of Israel.
A campaign official told AFP that the president, who has been hammered by Republicans who see him as too tough on Israel, personally intervened to have language on Jerusalem, a feature of past party platforms, restored.
The official, speaking on condition of anonymity, said Obama had also questioned why the party ever dispensed with language in the 2008 platform referring to America's "God-given" potential.
Amid chaotic scenes, Democrats began the second day of their nominating jamboree amending the platform they had adopted just 24 hours earlier.
Sensing the move may rile influential religious and Jewish voters, convention manager and Los Angeles mayor Antonio Villaraigosa, asked for approval of a revised document.
Proposing the motion, former Ohio governor Ted Strickland said "faith and belief in God is central to the American story" and "President Obama recognizes Jerusalem as the capital of Israel and our party's platform should as well."
But when a voice vote was called the "nays" appeared to match the "ayes."
"I -- I -- I guess, I'll do that one more time," said an obviously flustered Villaraigosa.
Despite the second attempt leading to a similar response, Villaraigosa declared: "In the opinion of that chair, two-thirds have voted in the affirmative. The motion is adopted, and the platform has been amended."
That sparked a chorus of boos from the floor, while supporters tried shambolically to cheer the passing of the measure.
"I only have concerns about those who said 'no,'" Ruben Diaz, Jr, president of New York City's Bronx borough, told AFP. "The people of Israel deserve to know that America has their back."
Since 1992, Democrats have stated unequivocally that "Jerusalem is the capital of Israel," but the US embassy remains in Tel Aviv pending an agreement between the Israelis and the Palestinians on "final status" issues.
The status of Jerusalem is one of the most contentious issues of the long-running Israeli-Palestinian conflict and a thorny issue in US politics.
Democrat and Republican White Houses have long stated that Jerusalem's final status should be decided by negotiations between the two parties.
But thanks in large part to the influence of Jewish voters in key battleground states like Florida, relations with Israel are a hot button issue in US elections.
The platform is a largely symbolic document, which is often ignored by the powerful executive branch.
US President Barack Obama ordered Democrats Wednesday to reinsert references to God and Jerusalem in their party platform, prompting boos from many angry delegates.