(Amber Ferguson/The Washington Post)

Robert S. Mueller III, who served as director of the Federal Bureau of Investigation during the last two administrations, brings to his new role as special counsel a proven willingness to take on a sitting president.

In a high-drama episode in 2004, he and then-Deputy Attorney General James B. Comey were preparing to resign from their positions if President Bush reauthorized the National Security Agency’s warrantless wiretap program without changes. Bush backed down.

Now, Mueller is charged with another politically fraught mission: the investigation of possible coordination between President Trump’s associates and Russian officials seeking to meddle in the 2016 campaign.

Former colleagues said the ex- Marine Corps officer and former U.S. attorney, who was sworn in as FBI director a week before the 2001 terrorist attacks, is uniquely suited to the task.

“He doesn’t sway under political pressure,” said Thomas J. Pickard, who served as deputy director of the FBI under Mueller on Sept. 11, 2001. He noted that President Obama extended Mueller’s term, even after he had served through all eight years of the Bush administration. “For 12 years, he kept the FBI out of politics,” Pickard added.

Then-FBI Director Robert Mueller is sworn in during a hearing before the House Judiciary Committee in 2013. (Alex Wong/Getty Images)

George J. Terwilliger III, who has known Mueller since both were assistant U.S. attorneys three decades ago, said that “if a special counsel had to be appointed, I think Bob is a terrific choice.”

“I have no doubt that he will be even handed — including going hammer and tong after anyone who is leaking investigative or classified information,” said Terwilliger, who served as deputy attorney general while Mueller led DOJ’s criminal division. “Bob’s got a career that is marked by handling the highest-profile matters out of the public eye with his nose to the grindstone and attention to the business.”

Neil MacBride, a former U.S. attorney who has worked with Mueller in a variety of jobs, called him “the real deal, the most respected prosecutor in America.”

A former deputy attorney general who later did a stint prosecuting homicide cases in Washington, Mueller is a known as a no-nonsense, relentless prosecutor with a deep reverence for the rule of law.

“The most devastating thing that can happen to an institution is that people begin to shade and dissemble,” he told Washingtonian magazine in 2008.

Mueller also has long ties to major players in the tumultuous political story that has engulfed Trump’s presidency. Deputy Attorney General Rod J. Rosenstein, who tapped Mueller for the task, served under him at the Justice Department as a criminal prosecutor. Comey, whom Trump abruptly fired last week, was his ally during the Bush era and then succeeded him as FBI director.

Until his surprise appointment Wednesday, Mueller served as a partner at WilmerHale, a firm that represents former Trump campaign chairman Paul Manafort, Trump’s daughter Ivanka and Jared Kushner, the president’s son-in-law.

Robert T. Novick, the firm’s co-managing partner, said Wednesday that Mueller had left effective immediately. Two WilmerHale partners who worked with Mueller in the past are expected to join him in the special counsel’s office, according to Novick: Aaron Zebley, Mueller’s chief of staff when he was FBI director, and James L. Quarles III, who worked with Mueller at the law firm in the 1990s.

Mueller grew up in Philadelphia and went to St. Paul’s School, the elite prep school in New Hampshire, where he played hockey with John F. Kerry, the former secretary of state.

At Princeton, he was inspired to join the Marine Corps by a former student who died in Vietnam, according to Washingtonian. He led a rifle platoon in Vietnam, eventually receiving numerous commendations, including the Purple Heart and the Bronze Star.

After graduating from the University of Virginia Law School, Mueller worked for a dozen years as an assistant U.S. attorney in San Francisco and Boston, where U.S. attorney William Weld described him as a “straight arrow.”

“He didn’t try to be elegant or fancy; he just put the cards on the table,” Weld told Washingtonian.

Mueller succeeded Weld as U.S. attorney in Boston and then went to Washington in 1989 as an assistant to Attorney General Richard L. Thornburgh, eventually rising to be chief of the criminal division. During his tenure, he worked on high-profile cases such as the prosecution of former Panamanian dictator Manuel Antonio Noriega and the terrorist bombing of Pan Am Flight 103.

After a stint at a private law firm, Mueller took a big pay cut to work as a homicide prosecutor in Washington for U.S. Attorney Eric H. Holder Jr. — a move that friends said showed how much prosecuting was in his blood.

Holder told The Post that Mueller called him and explained he was “shaken” by killings in the city and wanted a chance to be a line prosecutor and do something about it.

Holder called the conversation “one of the most extraordinary calls I’ve ever gotten.”

Holder later tapped Mueller to serve as U.S. attorney in San Francisco.

In 2001, Bush selected him to replace Louis J. Freeh as FBI director, a position friends said Mueller had long sought. He was unanimously confirmed by the Senate.

A week later, planes hit the World Trade Center and the Pentagon, upending his job and the bureau.

Pickard, who briefly served as his deputy, said that in the days after the attack, Mueller worked so hard that Pickard told his wife he needed to take a break: “I told her, ‘He’s killing us,’ ” Pickard recalled.

“He had a tremendous work ethic,” Pickard said. “He wouldn’t think anything of staying there until 9, 10, 11 p.m. at night and then showing up at 6 a.m. the next day, bright-eyed and bushy-tailed and ready for work.”

Among Pickard’s duties was to brief Mueller. He said the FBI director would often reject summaries, asking instead to review the full notes taken by agents from their interviews. For exercise, he would stand for hours at a lectern, reading page after page. “He’s a real student — getting down into the details,” he said.

Less than three years later, Mueller and Comey were involved in the standoff with other Bush administration officials over an effort to extend the warrantless wiretapping program run by the National Security Agency.

At one point, Comey rushed to hospital bedside of Attorney General John D. Ashcroft to try to persuade him not to certify the extension sought by White House counsel Alberto R. Gonzales and Chief of Staff Andrew H. Card Jr. Comey, who was serving as acting attorney general while Ashcroft recovered from gall bladder surgery, had refused to support the program’s continuation in its form.

Mueller arrived at the hospital shortly after the confrontation in Ashcroft’s room. He told the FBI agents guarding the room not to allow anyone else in to see Ashcroft without Comey’s permission.

When the Bush administration tried to proceed with the extension, Comey, Mueller and other Justice Department officials threatened to resign — forcing Bush to change the program.

After President Barack Obama was elected, he asked Congress to extend Mueller’s term past the statutory 10-year appointment, making him the second-longest-serving FBI director, after J. Edgar Hoover.

“Like the Marine that he’s always been, Bob never took his eyes off his mission,” Obama said when Mueller stepped down in 2013, adding: “I know very few people in public life who have shown more integrity, more consistently, under more pressure than Bob Mueller.”

As a partner at WilmerHale, which Mueller joined in 2014, he was frequently tapped by major corporations and institutions to conduct complex, sensitive internal investigations. Among his recent clients was the defense contractor Booz Allen Hamilton, which hired him to review the company’s security procedures after one of its employees was charged with stealing classified data from the NSA. Another was the National Football League, which tapped Mueller to examine how the league handled a domestic abuse case involving former Baltimore Ravens running back Ray Rice.



Alice Crites and Matt Zapotosky contributed to this report.