Robert Mueller (Diego M. Radzinschi/NLJ)

Robert Mueller III is leaving his perch in private practice to re-enter law enforcement, taking on the high-profile, politically precarious and weighty role as special counsel investigating Russia’s efforts to influence the 2016 presidential election. Two other lawyers, Aaron Zebley and James Quarles III, also left.

Deputy Attorney General Rod Rosenstein appointed the post-9/11 FBI director and Wilmer Cutler Pickering Hale and Dorr partner Wednesday “to ensure a full and thorough investigation of the Russian government’s efforts to interfere in the 2016 presidential election.”

The investigation will examine any links between individuals on Trump’s campaign and the Russian government. Mueller will have the authority to prosecute if needed.

“I accept this responsibility and will discharge it to the best of my ability,” Mueller said in a statement provided to the NLJ.

President Donald Trump said he looks forward to the investigation concluding quickly.

“As I have stated many times, a thorough investigation will confirm what we already know – there was no collusion between my campaign and any foreign entity,” Trump said in a written statement.

Mueller agreed to resign from Wilmer to avoid any conflicts of interest. The firm expects the latter two attorneys will join Mueller in the investigation, a firm spokesperson said.

Zebley was Mueller’s former FBI chief of staff, and litigator Quarles was the former managing partner of the Washington, D.C., office of predecessor firm Hale and Dorr, and was a former Wilmer executive committee member. Quarles also worked as an assistant special prosecutor for the Watergate investigation. All three lawyers’ professional biographies were scrubbed from the firm’s website Wednesday.

Widely respected as one of the longest serving directors of the FBI, Mueller left the department in 2013 and joined Wilmer the following year.

In private practice, Mueller worked on a range of issues including cybersecurity, criminal litigation and internal investigations. Last year, he was appointed to oversee settlement negotiations in class action lawsuits over Volkswagen A.G.’s emissions scandal.

U.S. District Judge Charles Breyer, who oversees the Volkswagen case in San Francisco, praised Mueller at the time. “There are few, if any, people with more integrity, good judgment, and relevant experience than Mr. Mueller,” Breyer wrote.

Since April, Mueller has been in charge of the distribution of almost $1 billion to victims and automakers affected by Takata’s defective airbags.

He also served as the NFL’s independent investigator into the league’s handling of a violent episode involving former Baltimore Ravens player Ray Rice.

At the time of that appointment, in 2014, Andrew Weissmann, a former FBI general counsel who worked for Mueller, said, “You’re not going to hire Robert Mueller if you’re looking for a white wash.”

Indeed, few lawyers and government-focused law firms have built resumes as impressive as Mueller and Wilmer when it come to working for Democrats, Republicans and as independent counsel.

Mueller ran the FBI for for more than a decade. President George W. Bush appointed him in 2001, a week before the Sept. 11 attacks. Though FBI directors have a 10-year tenure, President Barack Obama asked Congress to allow him to stay on another two years.

Mueller served as U.S. Attorney for the Northern District of California prior to joining the FBI. He graduated from Princeton University in 1966 and went on to receive his J.D. from the University of Virginia.

Though unrelated to the current political scandal, Mueller is named in a to-be-resolved U.S. Supreme Court case that alleges he’s personally responsible, alongside former Attorney General John Ashcroft, for discrimination against Arab and Muslim detainees after 9/11. A decision is expected by the end of June. The case bears similarities to the court challenges against Trump’s travel ban because it reflects a generalized suspicion of Arab and Muslim connections to terrorism.

In recent years, Wilmer has stocked up on former high-ranking government officials such as Mueller for its ranks, including former Obama-era Deputy Attorney General David Ogden and a Bush-era ambassador to Germany, Robert Kimmitt.

Partner Reginald Brown, who worked in the Bush White House and runs the firm’s financial institutions group and congressional investigations practice, is advising Paul Manafort as of this spring. Manafort, who ran Trump’s presidential campaign for six months, may be ensnared in the Russia investigation because of a consulting client he represented in Ukraine who had ties to the Kremlin.

Top Clinton administration alumni at Wilmer include former Solicitor General Seth Waxman and former Deputy Attorney General Jamie Gorelick, who’s boosted her own resume in recent months by advising Ivanka Trump and Jared Kushner on government ethics.

NLJ reporter Marcia Coyle contributed to this report.

Cogan Schneier covers litigation in Washington, D.C. for the National Law Journal and Law.com. Contact her at cshneier@alm.com. On Twitter: @CoganSchneier. Katelyn Polantz is based in Washington, D.C., and writes about government and the business of law. She can be reached at kpolantz@alm.com. On Twitter: @kpolantz