He Once Launched a Grenade for Trump. Now He’ll Be White House Counsel.

In August of 2023, a trio of lawyers took a call that would end up vaulting them to the highest levels of the federal government.

At the time, Donald J. Trump, still reeling from the mob attack on the Capitol and the prosecutions that followed, remained toxic in many legal circles. Several members of his legal team faced professional repercussions, including disbarment, for their conduct in representing him.

But then the phone was ringing, and on the other line was Mr. Trump. Will Scharf, D. John Sauer and Michael Talent — all graduates of elite law schools who were practicing together in St. Louis — made their pitch to the Trump campaign. They were hired, and later prevailed in front of the Supreme Court in a case that granted Mr. Trump broad immunity from criminal prosecution.

All three men will now occupy some of the most powerful positions in government.

Mr. Sauer is the solicitor general, still battling for Mr. Trump in front of the Supreme Court. Mr. Talent is one of Mr. Sauer’s top deputies. And next month, the 40-year-old Mr. Scharf — who keeps a pair of cowboy boots in his truck, drinks black coffee at any time of day and once fired a grenade launcher in a TV ad — will become the White House counsel, the man tasked with giving Mr. Trump in-house legal advice.

The job of the White House counsel, in particular, has proved to be a particularly tricky ***ignment under Mr. Trump, who is known to hear what he wants to hear and to disregard the rest. It remains to be seen whether Mr. Scharf will try to guide Mr. Trump away from some of his most extreme impulses.

Mr. Scharf has at times shown a willingness to clash with other members of the administration when he believed their advice ran afoul of the Constitution. Last year, in his role as the White House staff secretary, he wrote two secret memos opposing ideas being floated by the powerful Trump aide Stephen Miller: that the president suspend due process rights for undo***ented immigrants, and that he consider invoking the Insurrection Act to deploy the military on U.S. streets as protests grew against deportation sweeps.

Mr. Scharf has stood next to Mr. Trump as the president has rolled out some of the most polarizing elements of his agenda, including many that have been blocked by the courts. Mr. Scharf declined a request for an interview. But friends and colleagues who know him well say that he does not see standing up to Mr. Trump as part of his job.

“His view is that his job is not to tell the president all the things he can’t do, but how he can do things,” said Mike Fragoso, a college friend of Mr. Scharf’s and a former counsel to Senator Mitch McConnell, Republican of Kentucky. “And I think a guy like Will’s attitude is: He works for the president. He doesn’t work for Will Sharf. And because he has that attitude, I think he is in a position to give the best, honest advice from the president’s perspective.”

In Mr. Trump’s second term, Mr. Scharf has also served as the chair of the National Capital Planning Commission, where he oversaw the rapid approval of several of the president’s signature projects, including his $400 million ballroom on the White House grounds. In that role, critics saw Mr. Scharf as little more than a yes man.

“I think it’s unquestionable that the way he served on the National Capital Planning Commission was as a rubber stamp from Day 1,” said Jon Golinger of the progressive organization Public Citizen, which has raised concerns about the president’s construction spree in the nation’s capital.

Mr. Scharf resigned from his role on the planning commission on Tuesday.

During Mr. Trump’s first term, Donald F. McGahn II, the White House counsel, clashed with the president over the Russia inquiry, refusing to carry out certain directives, such as ordering the firing of Robert S. Mueller III, the special counsel. His replacement, Pat A. Cipollone, and Mr. Cipollone’s deputy, Patrick F. Philbin, also pushed back against Mr. Trump’s efforts to overturn the 2020 election. Mr. Cipollone warned that pushing certain plans related to the events of Jan. 6, 2021, could result in severe legal jeopardy.

The current White House counsel, David Warrington, who is leaving the government at the end of the month and was also a member of Mr. Trump’s private legal team, has not clashed with the president publicly. Instead, he worked to enable some of the president’s most aggressive moves, including invoking emergency powers, sending troops into cities and investigating Mr. Trump’s perceived foes.

John T. Lamping, a friend of Mr. Scharf’s from Missouri who worked with him on Republican campaigns, said that Mr. Scharf sees his role as carrying out the agenda of his boss.

“He considers whoever he’s working for, in any capacity, that that guy’s the boss, and his job is to serve that person to his greatest capacity,” Mr. Lamping said, adding that Mr. Scharf would refer to the Missouri governor as “the boss.”

“‘He’s calling. The boss is calling. Got to go,’” Mr. Lamping said, imitating Mr. Scharf. “That’s kind of his approach to things. It doesn’t surprise me he’s done so very well in his role.”

Mr. Scharf was not always a cowboy boot-wearing Missourian. He grew up in a wealthy Manhattan family and attended Ivy League schools.

According to The Daily Princetonian, Mr. Scharf’s parents, Fiona and Michael, were the initial major donors to the Center for Jewish Life and the Scharf Family Chabad House at Princeton, where Will Scharf would major in history.

On campus, Mr. Scharf made a name for himself as a conservative crusader — with a theatrical flair — and as a conscientious student.

“My impression of him, almost immediately, was that he was very disciplined and he was highly motivated,” said Mr. Scharf’s thesis adviser, Paul Miles, an Army veteran who called Mr. Scharf “one of my best Princeton students majoring in history.”

Mr. Scharf also served as the press secretary for the College Republicans. He ran, unsuccessfully, for student body president, pitching himself as an outsider. Mr. Scharf told The Daily Princetonian that he represented “the average angry student on campus, the student who is not happy with the way things are on campus.” His campaign included “a 12-hour speaking marathon in which he challenged administrative policies ranging from grade deflation to the fire code” in the middle of winter, according to a news account at the time.

He also wrote a column in The Princeton Tory, the university’s conservative magazine, where he objected to the influence that centrist candidates had in the G.O.P.

“From free speech issues to immigration to judicial appointments to tax cuts, John McCain has snubbed the Republican Party time after time after time,” Mr. Scharf complained in The Tory, after the Arizona senator was chosen as the Republican presidential nominee in 2008.

At Princeton, Mr. Scharf did have one run-in with the law.

In 2008, when he was a senior, he was charged with serving alcohol to minors and maintaining a nuisance at an off-campus club. Following the dismissal of all charges, his lawyer threatened to file a lawsuit against the police for “false arrest, malicious prosecution and federal civil rights claims,” according to The Daily Princetonian.

Upon graduation, Mr. Scharf attended Harvard Law School, where he became president of the university’s chapter of the Federalist Society, the influential conservative group.

Friends described him as someone with intense interests in law, history and research, prone to staying up all night going down rabbit holes on intellectual subjects.

“He knows a ton about the most esoteric things,” said LeElle Slifer, a partner at the law firm King & Spalding and a friend of Mr. Scharf’s from law school. “He knows a lot about the history of the Bank of New York. If you ever get him talking about that, Will can tell you all about it.”

The connections to the Federalist Society would prove useful for Mr. Scharf. Years later, groups ***ociated with Leonard Leo, a powerful figure there, would bankroll Mr. Scharf’s run for attorney general in Missouri.

Mr. Scharf moved to Missouri in 2011 to clerk for Raymond Gruender, a federal judge appointed by President George W. Bush. He later worked in the state as a policy chief to former Gov. Eric Greitens, a Republican who resigned in 2018 amid scandal, and then as a federal prosecutor, targeting violent crime.

After Mr. Greitens resigned, Mr. Scharf moved to Washington, where he worked on the Supreme Court nominations of Brett M. Kavanaugh and Amy Coney Barrett, as part of the conservative Judicial Crisis Network and the Justice Department’s Office of Legal Policy.

Mr. Scharf returned to Missouri and unsuccessfully ran for attorney general. In one campaign ad, Mr. Scharf fired a grenade launcher into boxes that were labeled as carrying criminal files against Mr. Trump.

Since joining the Trump administration, Mr. Scharf is perhaps best known as the presenter of Mr. Trump’s executive orders during made-for-TV signings in the Oval Office. And as the chair of the National Capital Planning Commission, Mr. Scharf has ensured the president’s favored projects get approved, and quickly.

During the rush to approve the ballroom project, Mr. Scharf clashed with Mr. Golinger when Mr. Golinger challenged his credentials to sit on the board. Mr. Scharf ran through a list of his qualifications before adding: “To say that I lack the credentials to serve on this commission is frankly insulting.”

Still, Mr. Golinger said he hoped to see an independent streak in Mr. Scharf.

“Certainly on the ballroom, I saw no independence, but I don’t know whether behind closed doors he might have a stiffer spine,” Mr. Golinger said. “But certainly, the hope of the country is that when things are on the line, if the law and the Constitution require something, that we certainly all hope he’ll side with the law and the Constitution over Donald Trump.”

Kitty Bennett contributed research.