Years before President Trump returned to the White House, his budget chief, Russell T. Vought, began mapping out a plan to shrink the federal government.

In Mr. Vought’s design, spending would be slashed by about $9 trillion over the next decade. Entire federal programs — from housing vouchers to student loans — would be eliminated. The government would fire thousands of civil workers, including those who investigated tax fraud. And Washington would restrict aid to the poor, requiring Americans to work in exchange for benefits.

The ideas formed the bedrock of Mr. Vought’s plan to end the “woke and weaponized” bureaucracy, a policy guide he issued in 2022 for fellow conservatives entering a key budget battle. His full vision did not come to fruition at the time, but the roughly 100-page blueprint has taken on heightened significance since Mr. Trump won re-election — and reinstalled Mr. Vought to his perch — foreshadowing their shared aim to reel in the size and reach of government.

In the perennial fight over the federal balance sheet, few officials are more important than Mr. Vought. As head of the Office of Management and Budget, he wields vast power over the United States government, its workers and the millions of people whose lives are shaped by the ebb and flow of federal funds.

Mr. Vought brings an aggressive style to the job, one revealed in podcast interviews and public writings, particularly in the years after Mr. Trump’s 2020 defeat. A longtime budget expert, he sketched out a vision for expansive presidential power in Project 2025, the conservative blueprint prepared by the Heritage Foundation for Mr. Trump. And in 2021, Mr. Vought founded his own organization, the Center for Renewing America, which describes itself as dedicated to “God, country and community.”

There, Mr. Vought refined an ambition to marry extreme fiscal austerity with Christian values, pledging to eliminate federal programs seen as too wasteful, “woke” or secular. In scrutinizing the budget, his approach has made him a natural ally of Elon Musk and his so-called Department of Government Efficiency.

Now back at O.M.B., Mr. Vought has assembled a team of like-minded advisers who are working to prepare Mr. Trump’s 2026 budget proposal. That blueprint may guide Congress in its work to extend a set of expensive and expiring tax cuts enacted in Mr. Trump’s first term.

Documents reviewed by The New York Times showed that as recently as late February, O.M.B. staff were compiling recommendations for sweeping cuts to programs that Republicans have long wanted to slash. Those cuts include imposing work requirements for recipients of food stamps, ending public service student loan forgiveness and phasing out certain federal Medicaid funds for states.

The president and Mr. Vought also subscribe to the idea that the White House should have expansive powers over the nation’s purse strings, halting or canceling federal spending even if Congress instructs otherwise. That stance has emboldened the White House to already interrupt the distribution of billions of dollars, including foreign aid, infrastructure spending and payments to food banks.

The delays have provoked lawsuits, and in a largely unnoticed move, they have triggered an investigation by the Government Accountability Office, a nonpartisan watchdog established by Congress that acknowledged its inquiries in February. Some Democrats contend that the budget office has violated the law in other ways, after it quietly disabled a government website on Monday that tracked the regular outflow of federal dollars.

“Taking down this website is not just illegal, it is a brazen move to hide this administration’s spending from the American people and from Congress,” said Senator Patty Murray of Washington and Representative Rosa DeLauro of Connecticut, the leading Democratic appropriators, in a statement this week.

Mr. Vought declined through a spokeswoman to be interviewed. In a preamble to his 2022 policy guide, he wrote: “The evidence of America’s fiscal brokenness is everywhere.”

Mr. Vought’s calls for austerity are hardly novel in Washington, where policymakers often lament the nation’s growing $36 trillion debt, but they carry new force at a moment when Mr. Trump looks to reshape the federal bureaucracy.

As DOGE agents blitz federal agencies — shuttering entire programs, dismissing thousands of workers and burrowing into sensitive federal computer systems — Mr. Vought has toiled quietly to lay the foundation for “making these cuts permanent in the long term,” he explained in an interview with Fox Business in February.

The same month, Mr. Vought ordered agencies to submit detailed plans by March and April indicating how they would cut spending, lay off workers and sell office buildings to save money and ensure they “advance the president’s policy priorities,” according to a memo sent to agency leaders.

James C. Capretta, a former O.M.B. official now serving as a senior fellow at the right-leaning American Enterprise Institute, said Mr. Vought’s actions reflected the view that “the federal executive branch really should be at the service of a president in a manner that goes beyond professional management of the agencies.”

The reorganization arrived weeks after the budget office, under interim leadership while Mr. Vought awaited Senate confirmation, froze nearly all federal spending. While political pressure and multiple lawsuits forced the White House to rescind that policy, budget officials have continued to halt the disbursement of some federal payments. Another arrived this week, when the Trump administration essentially refused to spend about $3 billion in emergency money to combat narcotics and fund other programs, a move that drew a rare bipartisan rebuke in the Senate.

“Every day, there is a headline about another institution, about funding that has been discontinued,” said Skye Perryman, the president of Democracy Forward, a left-leaning advocacy group that has sued O.M.B. over its actions.

The freezes underscored Mr. Vought’s long-held belief that the budget office must serve as the White House “air-traffic control system,” as he wrote in a chapter for Project 2025. There, and in much of his work, Mr. Vought has long criticized civil workers, portraying some of their actions as motivated by their “own agenda.” He previously promised to put them “in trauma,” he said in a video first surfaced by ProPublica.

“They’re constantly hiding the ball,” Mr. Vought said during a May 2023 podcast interview, adding that Republicans needed to “micromanage the heck out of everything that is part of your agency, or make sure that your right arms are.”

With the help of Mr. Trump, the two men have established a team in recent weeks that echoes Mr. Vought’s views.

The roster includes Mark Paoletta, the budget office’s general counsel, who served with Mr. Vought during the first Trump administration and later at the Center for Renewing America. Mr. Paoletta represented Virginia Thomas, the wife of the Supreme Court justice Clarence Thomas, during a House investigation into Mr. Trump’s efforts to remain in power after the 2020 election. Mr. Paoletta drafted the since-revoked order that froze nearly all federal spending.

Jeffrey Bossert Clark, who is serving in a key O.M.B. office that oversees regulation, previously faced possible contempt of Congress charges for refusing to testify about accusations that he sought to undo the results of the 2020 race.

And Dan Bishop, whom Mr. Trump appointed as deputy director, is a former Republican congressman who, while serving in the North Carolina legislature, sponsored a bill that restricted transgender people from using their preferred public restrooms. The Senate confirmed his nomination on Wednesday.

Testifying this month, Mr. Bishop acknowledged that he agreed with those who believe the 2020 election had been rigged. The former congressman said the president had a mandate to pursue “an end to the waste and the Washington status quo.”

The comments angered Democrats, who recalled Mr. Trump’s first term, when he and Mr. Vought halted congressionally authorized aid to Ukraine in a standoff that laid the groundwork for House Democrats to impeach the president. The budget adviser maintained in 2021 — and, years later, at his own nomination hearing — that the White House had acted lawfully.

After the Senate confirmed him along party lines, Mr. Vought helped to secure a deal to stave off a government shutdown, wooing Republicans with a promise that the administration would take aggressive steps to slash spending. On Tuesday, Mr. Trump signaled that the White House could begin by submitting to Congress a formal list of proposed cuts, reflecting some of the savings identified by DOGE.

“I assume they’ll total everything up and get it to us,” Representative Ralph Norman, a South Carolina Republican and member of the House Budget Committee, said in an interview. “What the president will have will be sweet music to all of us who want a very conservative budget.”

At his Center for Renewing America, Mr. Vought in 2022 previewed his pursuit of stark cuts, targeting benefit programs including Medicaid. He proposed limiting its funding and eligibility, an idea he has resurfaced in recent weeks.

“You can get sizable levels of savings and reforms,” Mr. Vought told the Senate Budget Committee this year.

The term “woke” appeared 77 times in Mr. Vought’s document. The proposal looked to slash the “woke agenda” at the Centers for Disease Control and Prevention, for example, targeting money meant for “niche and small population groups.” It proposed jettisoning billions of dollars in “woke foreign aid spending”; eliminating entire programs for lesbian, gay, bisexual and transgender communities; and striking the “secular, woke religion” of climate change from the federal ledger.

“That is the central and immediate threat facing the country — the one that all our statesmen must rise tall to vanquish,” Mr. Vought wrote in the preamble to his budget. “The battle cannot wait.”

Alan Rappeport contributed reporting.