Mr. Deese urged the president to go big, maintaining the cost and ambition of the sweeping expansion of government in the economy that Mr. Biden had promised in the campaign. He prevailed: Mr. Biden later announced a $4 trillion economic agenda.
Mr. Deese helped push that agenda through Congress by building relationships with swing-vote Democrats and moderate Republicans. He and a top Biden aide, Steven J. Ricchetti, camped out in the office of Senator Rob Portman, Republican of Ohio, in the waning days of negotiations over the infrastructure bill. Surrounded by Ohio sports jerseys, sustained by ordered-in salads, they hammered out the final details of what became Mr. Biden’s first big bipartisan win.
Senators in those negotiations praised Mr. Deese for responding frankly to their concerns, in language that explained how legislative tweaks would affect people and businesses in the country.
“Economists can — they can put you to sleep, and they talk, and when they get done, you don’t know what the hell you’ve heard,” Senator Jon Tester, Democrat of Montana, said in an interview. “That isn’t the case with Deese.”
Senator Bill Cassidy, Republican of Louisiana and a key negotiator in the infrastructure talks, said that Mr. Deese was “a good poker player, and he’s a good negotiator. But once the commitment was made, I trusted that the commitment would be fulfilled.”
Mr. Deese brought more climate expertise to the National Economic Council than any previous director, and it was on that issue that his congressional relationships paid the biggest dividends for Mr. Biden. In July, after months of negotiations, Senator Joe Manchin III, Democrat of West Virginia and a key swing vote, signaled to Democratic leaders that he could not support the climate bill Mr. Deese had helped fashion, apparently dooming the effort.
But the following Monday, Mr. Manchin called Mr. Deese, with whom he had built a close relationship, including a zip-lining trip together. Mr. Manchin told Mr. Deese he still wanted to find agreement on a bill and invited him to the Capitol to continue talks that also included Senator Chuck Schumer of New York, the majority leader.
Mr. Deese barely slept for the next week, colleagues say, as the negotiations wore on in secret and ultimately produced the Inflation Reduction Act.