Joe Biden has wasted no time in getting to work in the White House.
The US president signed a flurry of executive orders in the hours after he was sworn in, including to rejoin the Paris climate agreement.
He has prioritised tackling the coronavirus pandemic, urging people to wear masks as the vaccine is rolled out, as well as the economy.
We take a look at five of Biden's key cabinet picks.
John Kerry – climate and environment
The former secretary of state, John Kerry, takes on a new cabinet-level position to lead on climate - underlining Biden's commitment to addressing environmental issues.
There are reportedly more than 100 domestic environmental regulations which were reversed by the Trump administration, which Kerry will oversee decisions on.
He will be joined by Michael Regan, head of the Environmental Protection Agency, and Gina McCarthy, as White House climate coordinator.
Janet Yellen – treasury
A former chief of the United States' central bank, the Federal Reserve, Yellen has been credited for her role in helping to steer the economic recovery after the 2008 financial crisis.
She will be the first woman to serve as treasury secretary, a position which advises the president on all economic and financial issues, and has rare support from both sides of the aisle.
Yellen will play a key role in Biden's economic recovery plans through the pandemic and beyond.
Antony Blinken – state department
Blinken is no stranger to working alongside Biden as he served as deputy secretary of state and deputy national security advisor in the Barack Obama administration, in which Biden was vice president.
As secretary of state, he will be chief foreign affairs advisor and the first cabinet member after the vice president in the line of succession.
Blinken, a long time advocate of humanitarian intervention in cases of mass atrocities, shares Biden's overall approach to international relations, with particular focus on Iran and Afghanistan.
Merrick Garland – attorney general
Widely respected, Garland is Biden's nominee for the attorney general position which heads the Department of Justice and serves as the chief lawyer of the federal government.
In 2016, the Republican-controlled Senate turned down his nomination to the Supreme Court under then-president Obama.
His appointment would mirror Biden's hopes of restoring the department's independence from the White House and improving morale, which had taken a hit under Trump.
Lloyd Austin – defence
Austin, a retired four star general, is another who has a close working relationship with Biden from the Obama administration when he served as the US commander in Iraq and led the US response to ISIS.
If appointed, he will be the first African American to serve as defence secretary and head of the Pentagon.
Though his appointment would need a waiver from Congress as the civilian position requires by law to be filled by someone who has been retired for at least seven years. Austin has only been retired for four.
It happened under Trump, who initially appointed James Mattis, but lawmakers may be reluctant to do so again.
Other notable cabinet picks
Other notable picks include Alejandro Mayorkas as secretary of homeland security, Pete Buttigieg as secretary of transportation, and Deb Haaland as secretary of the interior.
After Biden has decided on his picks, his nominations are presented to the Senate for confirmation by a simple majority (more than 50 percent).
For the first time in six year the Democrats hold the majority in the Senate, with newly appointed vice president Kamala Harris serving as the tiebreaker between the two parties.