Washington (CNN)Former US Ambassador to Ukraine Marie "Masha" Yovanovitch -- a highly respected career diplomat who unwittingly became one of the central figures in the impeachment drama -- has retired from the State Department.

Yovanovitch leaves after more than three decades in the foreign service. She was described as "someone who has never been hungry for the spotlight," by one former State Department official.

It is unclear when exactly Yovanovitch retired, but the official said it was sometime in the last two weeks. She had most recently been serving as a senior State Department fellow at Georgetown University.

She was removed from her post as the US ambassador in Kiev in May 2019 after a targeted campaign against her led by allies of President Donald Trump.

NPR was the first to report on Yovanovitch's retirement. The State Department did not immediately reply to a request for comment. 

Yovanovitch served as a witness in the House impeachment inquiry, testifying both publicly and privately. She was repeatedly maligned by the President -- including on a call with Ukrainian President Volodymyr Zelensky. She said she was "devastated" to find out that Trump had discussed her in such a negative way during his call with Zelensky in July. She said Trump's comments about her "sounded like a threat." Recent evidence suggested she may have been surveilled while serving in Ukraine.

Although the diplomatic corps continually rallied to her side, Secretary of State Mike Pompeo repeatedly failed to defend her from attacks. On Friday, Pompeo denied that he felt any "moral tension" about how she had been treated.

"We delivered for the President of the United States on a Ukraine policy that will benefit the American people I hope for years and years to come," Pompeo said in an interview with ABC News.

Yovanovitch is the fourth State Department official tied to the impeachment to leave -- following former US Special Representative to Ukraine Kurt Volker, former Pompeo adviser Michael McKinley and Ambassador Bill Taylor, who took over as the top US diplomat in Kiev following her departure.

In her public testimony in November 2019, Yovanovitch offered a strong defense of the work of career foreign service officers -- and warned of the impact the attacks were having on the diplomatic ranks.

In her opening statement, Yovanovitch sought to defend her work and that of her colleagues in the foreign service and called upon the leadership in the State Department to do the same. Her eloquent and forceful assessment of foreign service officers' service and sacrifices earned praise and pride from the more than half a dozen current and former State Department officials who spoke to CNN.

"We take our oath of office seriously, the same oath that each one of you take, 'to support and defend the Constitution of the United States against all enemies, foreign and domestic' and to 'bear true faith and allegiance to the same,'" she told the lawmakers.

Contrasting the "perception that diplomats lead a comfortable life throwing dinner parties in fancy homes," Yovanovitch described her own tenure in the foreign service: moving 13 times, serving in five hardship posts, being stationed in Somalia during the civil war, getting caught in crossfire in Russia.

"We are professionals, public servants who by vocation and training pursue the policies of the President, regardless of who holds that office or what party they affiliate with," she said of the foreign service.

"I count myself lucky to be a Foreign Service Officer, fortunate to serve with the best America has to offer, blessed to serve the American people for the last 33 years," Yovanovitch said.

LINK: https://edition.cnn.com/2020/01/31/politics/marie-yovanovitch-retires/index.html