Barack Obama will formally nominate his ex-rival Hillary Clinton as secretary of state on Monday and roll out the national security team he will charge with defusing multiple foreign crises.
The president-elect was also expected to publicly say he has asked US President George W Bush's Defence Secretary Robert Gates to stay on at the Pentagon and to name former marine general James Jones as his national security adviser.
Obama's formal presentation of Clinton at a press conference in Chicago nearly a month after his historic election triumph will cement a remarkable alliance following the pair's acrimonious Democratic primary duel this year.
"I can confirm that she will be in Chicago tomorrow to be named secretary of state," a person close to Clinton told AFP.
Obama and vice president-elect Joseph Biden will name the team just days after the Mumbai terror assaults handed them a fresh South Asia crisis to add to the plethora of US national security challenges.
After taking office in January at a time of rare national peril, the Obama team must work out how to extricate US troops from Iraq, deal with the Iranian nuclear drive and address deteriorating conditions in the war in Afghanistan.
At the same time, the US economy in meltdown and successive market and financial crises are cascading around the world, threatening to further destabilise a fractious global security environment.
As well as Gates and Jones, sources said Obama will complete the top layers of his national security team with Arizona Governor Janet Napolitano as Homeland Security chief.
Pending Senate confirmation, long-time Obama foreign policy aide Susan Rice is also set to be formally named as US ambassador to the United Nations while retired admiral Dennis Blair is set to be Director of National Intelligence.
Former president Bill Clinton cleared the way for his wife to become the face of US foreign policy abroad by reaching a complicated agreement on his financial arrangements and future role on the world stage.
There had been fears her nomination could falter over the appearance of conflicts of interest between her husband's charitable foundation and lucrative speechmaking schedule, and US foreign policy.
Clinton has agreed to release the list of donors to his charitable foundation by the end of the year, officials on Obama's transition team said.
He has also agreed to submit future engagements, speeches and sources of income to the State Department and the White House and to take a more behind-the-scenes role in the daily running of his foundation, sources said.
Democratic Senator Jack Reed said the ex-president's "framework of transparency and disclosure" is a key step in defusing concerns about how he may influence his wife's work should she become the top US diplomat.
"I think the presumption will be that both the secretary of state Clinton and... former president Clinton will be very judicious in what they take on, because there's a new dimension here," Reed said on US ABC's This Week.
"The secretary of state and the former president are married, and I think that's going to set the standard."
Senator Richard Lugar, the ranking Republican on the Senate Foreign Relations Committee, agreed that Bill Clinton's agreement should help his wife's nomination.
"I plan to vote in favour of her confirmation," Lugar told ABC, while also praising Obama's "excellent selections" of his national security coterie.
The Obama transition team formally announced that the former first lady and the rest of the national security team would be introduced in a press conference at a Chicago hotel on Monday at 9.40am local time (0240 AEDT Tuesday).
Last week, Obama named intellectual heavyweights and big political egos for his economic team, in a move which reassured markets traumatised by the raging financial crisis.
He defended his decision to name big-time political players of the Clinton administration to his team, saying the troubled times dictate the need for experience in his economic and national security teams.
Selecting Gates, who is respected across the political aisle in Washington for his performance since taking over from Donald Rumsfeld two years ago, would allow Obama to honour his pledge to name at least one Republican cabinet member.
Jones, a former NATO commander, is also respected on Capitol Hill and may be sought by Obama for his expertise on the Afghan war.