Pope Francis welcomed US Secretary of State Antony Blinken to the Holy See on Monday for what the Vatican said was a friendly meeting.
Mr Blinken had a tour of the Sistine Chapel on the second day of his stay in Rome, where he was chairing a meeting of the US-led coalition against ISIS.
The audience with Francis came against the backdrop of a move by US bishops to reprimand Mr Biden for his tolerant stance on abortion.
But Vatican spokesman Matteo Bruni said the 40-minute meeting took place in a "friendly atmosphere".
Mr Blinken said the US would work with the Holy See to address global challenges such as caring for refugees and migrants.
He thanked the pontiff for his "leadership on the need to care for the environment and tackle the climate crisis".
The audience was the second in six weeks between the Pope and a senior Biden official after climate envoy John Kerry visited the Vatican in May.
The Pope expressed his affection and attention to the people of the US, Mr Bruni said.
Mr Blinken held separate talks with the Holy See's foreign policy chief and discussed issues including global vaccination efforts against Covid-19.
The diplomats "underscored the importance of addressing the challenges in Syria and Lebanon", the US State Department said.
Bishops clash with Biden
Mr Biden is the second Catholic president after John F. Kennedy but faces pressure from conservative bishops over his stance on abortion.
A group of bishops agreed this month to draft a statement that could potentially deny Holy Communion to any US leader who supports abortion rights.
The Pope has made no public comment on the debate within the polarised US clergy.
Mr Biden’s predecessor Donald Trump took a tougher line on abortion but clashed with the Vatican over his plans for a Mexican border wall and an accord signed between China and the Holy See.
Mr Blinken’s predecessor Mike Pompeo was denied a papal audience when he visited Rome last year, a move the Vatican said was aimed at avoiding favouritism towards Mr Trump’s camp weeks before the US election.
Pope Francis congratulated Mr Biden after his November election victory and shares priorities with the new president, such as the need to address climate change.
Mr Kerry revealed in May that the pontiff was planning to attend the Cop26 climate summit which Britain is hosting in November.
He described Pope Francis as “one of the great voices of reason and a convincing moral authority on the issue of the climate crisis”.
