Wednesday marks William Barr’s final day serving the Trump administration as Attorney General, a position the former prosecutor reportedly called a “great honor” in a letter to colleagues. 

What You Need To Know

  • Attorney General William Barr's final day under the Trump administration was Wednesday, Dec. 23

  • Barr reportedly called serving in the role a "great honor" in a letter to colleagues obtained by NBC News

  • Trump initially announced Barr’s resignation in a series of tweets on Dec. 14, claiming the two had a “very good” relationship 

  • Deputy Attorney General Jeffrey Rosen will take over Barr's duties

“Today is my last day as Attorney General,” Barr wrote in a letter obtained by NBC News. “As I told the President in my departure letter and reiterated during my final press conference on Monday, it has been a great honor to serve once again in this role.”

“Over the past two years, the dedicated men and women of this Department — including its operational components — have risen to meet historic challenges and upheld our vital mission to enforce the rule of law,” the letter reportedly continued. “I have been continually inspired by your professionalism and outstanding work. As I did almost 30 years ago, I leave this Office with deep respect for you, and I will always be grateful for your service to the Nation we love.” 

Barr had previously served as the 77th U.S. Attorney General under President George H.W. Bush. 

Deputy Attorney General Jeffrey Rosen will assume the role of Attorney General until President-elect Joe Biden takes office in January. Biden has not yet announced his pick for the nation’s chief law officer. 

The decision to leave his post just a month before Trump’s administration ends is an unusual one.

For most of his tenure, Barr has been a staunch ally of the president — but Trump grew increasingly frustrated with his Attorney General after Barr said the Justice Department found no widespread election fraud that would change the outcome of the election. Trump has also been angry that the Justice Department did not publicly announce it was investigating Hunter Biden ahead of the election, despite department policy against such a pronouncement. 

President Trump initially announced Barr’s resignation in a series of tweets on Dec. 14, claiming the two had a “very good” relationship. 

"Just had a very nice meeting with Attorney General Bill Barr at the White House," Trump wrote at the time. “Our relationship has been a very good one, he has done an outstanding job! As per letter, Bill will be leaving just before Christmas to spend the holidays with his family."

Barr has increasingly undercut the president in recent days, on Monday affirming he saw "no reason" to appoint a special counsel to look into potential election fraud or to name one for the tax investigation of President-elect Joe Biden’s son.

Barr, in his final public appearance as a member of Trump’s Cabinet, expressed the belief of federal officials that Russia was behind a massive hack of U.S. government agencies, contradicting the president.

The Associated Press contributed to this report.