Mr Biden arrived with his wife Jill at the lying in state shortly before 5pm on Sunday, ahead of his attendance at Monday’s funeral.
They were joined by the US ambassador to the UK, Jane Hartley.
Large crowds were gathered behind barricades near Buckingham Palace and Parliament Square Garden ready to take photos of the motorcade.
Some children were sitting on their parents’ shoulders trying to get a view.
Security was tight and road crossings were closed ahead of the visit as rumours spread through the crowd about the imminent arrival of the president and his entourage.
Mr and Mrs Biden were greeted at Westminster Hall by Black Rod Sarah Clarke.
Air Force One touched down at Stansted Airport just before 10pm on Saturday evening.
The president had been due to meet Prime Minister Liz Truss on Sunday, but the talks were cancelled on Saturday.
A “full bilateral meeting” was scheduled for Wednesday when the leaders are set to be in New York for the UN General Assembly.