WASHINGTON (Reuters) - Former Deputy Attorney General Rod Rosenstein, best known for his decision to appoint Special Counsel Robert Mueller in May 2017 to probe links between President Donald Trump’s campaign and Russia, has joined the law firm King & Spalding as a partner, the firm announced on Wednesday.

FILE PHOTO: Deputy Attorney General Rod Rosenstein speaks during his farewell ceremony at the U.S. Department of Justice in Washington, U.S., May 9, 2019. REUTERS/Leah Millis

In his new role, Rosenstein will work in the law firm’s special matters and government investigations group.

Rosenstein’s decision to appoint Mueller as Special Counsel thrust him into a spotlight that most deputy attorney generals do not experience in their tenures.

His decision was prompted by Trump’s firing of former FBI Director James Comey, a move that raised concerns about whether Trump was improperly obstructing the bureau’s investigation into his campaign.

Rosenstein faced staunch criticism from both Trump and his allies in Congress throughout Mueller’s investigation, and the possibility that he could be fired by Trump was often the subject of speculation.

Despite the criticism, Rosenstein defended his decision to appoint Mueller, and he continued to oversee the investigation even after Matt Whitaker temporarily took over as Acting Attorney General following the resignation of Attorney General Jeff Sessions.

Rosenstein perhaps faced the most pressure in September 2018, when the New York Times published an article claiming Rosenstein in 2017 had discussed secretly tape recording Trump and had tried to recruit Cabinet members to support removing him from office for being unfit.

Rosenstein called the story inaccurate, and though the article stoked Trump’s ire, he was able to remain on the job.

Rosenstein had planned to leave the Justice Department shortly after the Senate confirmation of Attorney General William Barr, but opted to stay longer in order to help see through the completion of Mueller’s investigation.

Mueller finalized his report in March 2019, and a redacted copy was publicly released in April.

In his report, he said his investigation could not establish evidence that Trump’s campaign illegally conspired with Moscow.

The report also presented unflattering details about how Trump attempted to impede the investigation, though Mueller did not make a determination as to whether Trump obstructed justice.

As such, Rosenstein and Barr later made their own determination, finding there was insufficient evidence to charge the president. He left the department in May.

“Rod Rosenstein is an exceptional trial lawyer, strategist and leader with unquestioned integrity and toughness,” King & Spalding Chairman Robert D. Hays, Jr. said in a statement.