That's the good news. The bad news is that he might have kicked off a chain of events that could bring his time as Prime Minister to a premature end. He now faces what will be two of the most painful days of his career back in London.
On Friday, Johnson will have to convince lawmakers across the political divide that they should back his new Brexit deal.
His reasons for voting against May were numerous and extended well beyond the backstop. And now he, Boris Johnson, must look the Brexiteers he led in the eye and say that his deal is worth 39 billion (about $50 million) where May's was worth nothing.
That's Friday. On Saturday, the rubber meets the road, when Johnson will bring his deal before Parliament for a special weekend sitting. He will have to spend the day sat in Parliament listening to his deal be criticized from all corners of the House of Commons. As Johnson's time at his first, and possibly last, summit as leader of an EU member state came to an end, he told media that he hoped when his "colleagues in parliament study this agreement, they will want to vote for it on Saturday."
Right now, the numbers are not there for Johnson. Generous predictions currently give him a narrow loss. But if everything falls apart for him in the next 48 hours, it could be a crushing defeat.
And he will be attacked from both the left and right. Those favoring a softer Brexit -- or no Brexit at all -- will say that Johnson wanted to irresponsibly drag the nation into the unknown. Hardline Brexiteers will say that he sold out the country to the EU.
And though Johnson enjoys healthy poll leads at the moment, his credibility would take an unavoidable blow if he is forced to request a Brexit extension.
Of course, none of this removes the fact that Johnson has done something he was repeatedly told could not be done. He's got a new deal and amazingly seems to have the entire EU behind him.
Despite the mountain before him, Johnson could be forgiven for seeing a way to the summit. As things stand, he needs the help of people he's spent his three months in power alienating if he's to do the impossible once again. And in Johnson World right now, nothing feels impossible.