If confirmed, Kerry would take the helm at the State Department from outgoing Secretary Hillary Rodham Clinton, who has long stated her intentions to leave early next year. Kerry, a longtime Massachusetts senator, is expected to be easily approved for the Cabinet post by his longtime Capitol Hill colleagues.
Obama will announce Kerry's nomination from the White House, said the official, who requested anonymity in order to discuss the president's decision before the announcement.
It was unclear whether Clinton would attend the announcement. The secretary fell and suffered a concussion last week, State Department officials said, and hasn't made public appearances since then.
Kerry's nomination could bring to a close what has become for the White House a contentious and distracting effort to name a new secretary of state.
Kerry was the Democratic nominee for president in 2004, losing a close election to incumbent George W. Bush. He's a decorated Vietnam veteran who was critical of the war effort when he returned to the U.S., even testifying in front of the Senate committee he eventually chaired.
Kerry's only other rival for the job, U.N. ambassador Susan Rice, faced harsh criticism from congressional Republicans for her initial accounting of the deadly September attack on Americans in Benghazi, Libya. Obama vigorously defended Rice, a close friend and longtime adviser, but GOP senators dug in, threatening to hold up her nomination if the president tapped her for the post.
Rice withdrew her name from consideration last week, making Kerry all but certain to become the nominee. People familiar with the White House's decision-making said support within the administration was moving toward Kerry even before Rice pulled out.
Kerry, 69, is the first Cabinet nomination Obama has made since winning a second term, and the first piece in an extensive shuffle of his national security team. The president is also expected soon to nominate a new defense secretary to take over for retiring Leon Panetta and a new director of the Central Intelligence Agency to replace former spy chief David Petreaus, who resigned last month after admitting to an affair with his biographer.
Kerry, the chairman of the Senate Foreign Relations Committee, has long sought the nation's top diplomatic post. Obama considered him for the job after the 2008 election before picking Clinton in a surprise move.
Since then, Obama has dispatched Kerry around the world on his behalf numerous times, particularly to tamp down diplomatic disputes in Afghanistan and Pakistan. He was also part of Obama's debate preparations team during the 2012 election, playing the role of Republican challenger Mitt Romney in mock debates.
Kerry also won praise from Obama aides for his sharp national security-focused speech at the Democratic National Convention in August. He memorably told delegates: "Ask Osama bin Laden if he's better off now than he was four years ago."
Before nominating Kerry, the White House consulted with congressional Democrats about the fate of the Senate seat he has held for five terms. An open seat in Massachusetts could give recently defeated Republican Sen. Scott Brown a chance to win back a job in Washington.
Democrats have sought to assure the White House that the party has strong potential candidates in the state that could keep Kerry's seat from falling into Republican hands.
Kerry has pushed the White House's national security agenda in the Senate with mixed results. He ensured ratification of a nuclear arms reduction treaty in 2010 and most recently failed to persuade Republicans to back a U.N. pact on the rights of the disabled.