For months, President Trump’s penchant for overhyping the speed at which he could negotiate complex trade deals has been the butt of Washington jokes.

“Ninety days ago, Donald Trump promised the world that his tariffs would lead to 90 deals in 90 days,” the Senate minority leader, Chuck Schumer, Democrat of New York, said earlier this month, adding: “By my count, he’s about 88 trade deals short.”

So on Sunday, when Mr. Trump announced a trade agreement with the European Union, it was not only his biggest trade deal to date, but also, politically, his most badly needed.

After going months without securing deals, Mr. Trump is now coming off his most productive stretch of trade negotiations, landing agreements in recent days with the Philippines, Japan and Indonesia as well as the European Union, which represents 27 countries.

The deal with the European Union, at least upon first impression, seemed to give Mr. Trump much of what he wanted.

“I’m very surprised how the European Union gave in to Trump’s demands,” said Douglas Irwin, a professor of economics at Dartmouth College. “I thought the E.U. would be the most prone to retaliation. And yet, they didn’t do it. They really gave in to most of what Trump wanted.”