The projected winner of the U.S. presidential election Joe Biden on Monday tapped Obama-era officials for top national security and economic roles, signaling a stark shift from the Trump administration's "America First" policies that disparaged international alliances and favored deregulation and tax cuts.

The picks include former Secretary of State John Kerry to take the lead on combating climate change. Biden is also expected to choose Janet Yellen, who was nominated by former President Barack Obama to lead the Federal Reserve, as the first woman to become treasury secretary.

Biden's emerging cabinet marks a return to a more traditional approach to governing, relying on veteran policymakers with deep expertise and strong relationships in Washington and global capitals. And with a roster that includes multiple women and people of color – some of whom are breaking historic barriers in their posts – Biden is fulfilling his campaign promise to lead a team that reflects the diversity of America.

Kerry, whose appointment does not require U.S. Senate confirmation, will have a seat on the National Security Council in the White House, the transition team said, marking the first time an official in that body will be dedicated to the climate issue.

Biden has pledged to reverse course on climate from Trump, who doubts mainstream climate science. Trump pulled the United States out of the 2015 Paris agreement on climate, and dismantled Obama-era climate and environmental regulations to boost drilling, mining and manufacturing.

While serving as the secretary of state under former President Obama, Kerry, 76, called climate change "the world's most fearsome weapon of mass destruction." In travels from glaciers in Greenland to the Solomon Islands, Kerry has emphasized cooperation on tackling climate change.

He will face a challenging task gaining the world's trust after Trump's rejection of climate diplomacy. 

Former Federal Reserve Chair Janet Yellen is expected to be nominated as U.S. Treasury secretary, confirmed by allies to the Biden campaign as per a Reuters report, breaking a 231-year gender barrier and putting a seasoned economist and labor market expert in charge of leading the country out of the steepest economic downturn since the Great Depression.

Yellen, 74, brings Biden decades of economic policy experience and is respected by Congress, international finance officials, progressives and business interests alike. 

She has called for opening fiscal spending taps to revive an economy wracked by the coronavirus pandemic and would be the first person to head the Treasury and the White House Council of Economic Advisers.

The post will present a host of new challenges for Yellen, whose policymaking experience in the past 20 years has largely centered on monetary, rather than fiscal, policy. For one, it means a far more political role than that she played in her long career at the Fed, an institution that goes to great lengths to distance itself from partisan politics.

Avril Haines, the former CIA No. 2, would be taking over as the chief overseer of a U.S. intelligence community beset by low morale and charges its work has been used for political attacks.

A lawyer from New York, judo brown belt and licensed pilot who once tried unsuccessfully to fly a small plane across the Atlantic Ocean, Haines, 51, is the first woman named as director of national intelligence, a post created after the September 11, 2001 attacks to coordinate the work of the 17 U.S. intelligence agencies.

Republican and Democratic Senate sources said Haines is expected to win confirmation, but not without some hard questioning about her role as deputy CIA director from August 2013 to January 2015 and her views on national security challenges, from Russia to cyber warfare.

If confirmed, Haines would confront low workforce morale fuelled by Trump's attacks on intelligence agencies and their assessments and his ousters of career officials he considered disloyal.

She would succeed John Ratcliffe, a former Texas congressman with scant intelligence experience when he was chosen in February by Trump after vigorously opposing Trump's impeachment.

Mayorkas, a former federal prosecutor in California, served as deputy secretary at the Department of Homeland Security (DHS) under the Obama administration. Mayorkas became one of Biden's first Cabinet selections as the Democratic former vice president prepares to take office on January 20.

If confirmed by the U.S. Senate, Mayorkas would become the first Latino and first foreign-born leader of the sprawling department created in the aftermath of the September 11, 2001. DHS, with about 240,000 employees, is responsible for border security, immigration enforcement, cybersecurity, disaster readiness and relief, and encompasses the U.S. Coast Guard and Secret Service.

Mayorkas, who turns 61 on Tuesday, was born in Havana and came to the United States when he was roughly a year old with his family, moving first to Florida and then California. He is currently a partner at the law firm WilmerHale.

"When I was very young, the United States provided my family and me a place of refuge," Mayorkas wrote on Twitter following the announcement. "Now, I have been nominated to be the DHS Secretary and oversee the protection of all Americans and those who flee persecution in search of a better life for themselves and their loved ones."

(With input from agencies)