Mr Biden set to work at the Oval Office after taking the oath of office with Chief Justice John Roberts on Wednesday as the 46th president of the United States.
President Biden “will take action – not just to reverse the gravest damages of the Trump administration – but also to start moving our country forward,” a statement detailing the executive orders said.
US President Joe Biden has begun to undo some of Donald Trump’s key policies, hours after being sworn in, tweeting earlier, “There is no time to waste when it comes to tackling the crises we face.”
President Biden signed 15 executive orders, firstly to boost the federal response to the coronavirus crisis.
Other reversals bothered on climate change and immigration, two core stances of Trump’s administration.
He signed an executive order beginning the process of re-joining the 2015 Paris climate agreement, from which Mr. Trump formally withdrew the US last year.
A series of measures will be enacted to tackle the coronavirus pandemic, strengthening enforcement with the mandate to wear masks and practice social distancing on all federal government property.
In addition, a new office will be set up to co-ordinate the response to the pandemic and the US will halt the process – begun by the Trump administration – of withdrawing from the World Health Organization (WHO).
The move to re-engage with the WHO was welcomed by UN Secretary-General Antonio Guterres who said it was “absolutely critical” for a more coordinated global response, his spokesman Stéphane Dujarric said.
He has also revoked the presidential permit granted to the controversial Keystone XL Pipeline, which environmentalists and Native American groups have fought for more than a decade.
The privately financed pipeline – estimated to cost about $8bn (£5.8bn) – would carry about 830,000 barrels of heavy crude a day from the oil sands of Alberta, in Canada, to Nebraska.
Barack Obama vetoed a bill approving construction of the pipeline in 2015 but the decision was overturned by President Trump.
On immigration, Biden has revoked the Trump administration’s emergency declaration that helped fund the building of a wall along the Mexican border and also ended a travel ban on some majority-Muslim countries.
Other orders cover race and gender equality.