And, he's been getting about. He's met Queen Elizabeth, David Cameron, the Duke and Duchess of Cambridge, Prince George, Prince Harry, Jeremy Corbyn, a bunch of young people at a town hall meeting and a gaggle of journalists who have been following him round since Thursday evening.
Such a packed schedule leaves quite the digital footprint. Here's some of the official - and not so official - snaps of the President of the United States as he went about his business on his three-day visit to the United Kingdom.
Obama certainly knows how to make an entrance, although onlookers were more than a little envious of his pre-arranged airport transfer.
BBC News (UK) (@BBCNews) April 21, 2016
Obama about to depart for central London on Marine One. Doesn't have to use tStansted Express & Central Line pic.twitter.com/EgnJaRCnEi— Chris Ship (@chrisshipitv) April 21, 2016
Travelling in style
Obama's car has been dubbed "the beast". Boris Johnson grumbled that foreign diplomats are excluded from paying the £11.50 a day congestion charge, which - with the size of the President's entourage - would have been a significant bounty.
The President has proved himself to be quite fond of the royals over the years. After a day with the Windsors where he wished the Queen a happy birthday and met Prince George, Obama said he thought the third-in-line to the throne was "adorable".
To be or not to be (in the EU)
Then it was on to the serious stuff - the reason Obama had come to the UK. He went big on his warnings of Brexit and said that the UK would be "at the back of the queue" if it voted to leave the European Union.
All the world's a stage
Obama's second day kicked off with some light entertainment - a private 10 minute rendition of William Shakespeare's most famous passage from Hamlet, to mark the 400th anniversary of his death. Is that Jeremy Corbyn lurking in the background? He wasn't far away ...
Man about town
Then it was back in front of a slightly larger audience, for a US-style town hall meeting with a bunch of Britain's future leaders and a few famous faces
Baz and Jez
Jeremy Corbyn had an "excellent" time with the president of the United States after he managed to secure a 90-minute private meeting with Barack Obama. The pair didn't stay to pose for photos, but Corbyn came beaming out.
Back on course
After a few hours darting about the place, it was time to relax - Cameron and Obama hit the golf course together on Saturday afternoon before they headed off to a private dinner later this evening with Matthew Barzun, the US ambassador to the UK.
Needless to say, Obama was in the driving seat ...