Brand was confirmed by the Senate May 22 following a Judiciary Committee hearing alongside Rosenstein.
The New York Times notes that Ms. Brand now "oversees a wide swath of the Justice Department, including the civil division, the civil rights division and the antitrust division".
Former CIA chief of staff Jeremy Bash said there are two reasons President Donald Trump is interested in firing Brand's immediate superior in the Russian Federation investigation, Deputy Attorney General Rod Rosenstein.
Deputy Attorney General Rod Rosenstein has been repeatedly criticized by Trump.
Brand will leave her position 'in the coming weeks, ' the statement said.
The release last week of a contentious Republican memo that accused the Justice Department and the F.B.I. of political bias raised new questions over whether Mr. Trump might seek to oust Mr. Rosenstein, who appointed the special counsel, Robert S. Mueller III. Brand's assistant has also left the Justice Department.
"Thank you, Rachel, for your kind words and, more importantly, for your strong leadership as our third in command at the department", Sessions said. Trump has flouted the possibility of firing him and, if he does, Brand would take over responsibility for Mueller's expanding probe. She was in line to oversee the investigation if Rosenstein stepped down. She received a job offer she could not turn down, according to NBC.
She is a graduate of Harvard Law School, clerked at the Supreme Court, she worked at the White House, in academia, and has served in leadership positions spanning three administrations. Andrew McCabe, the former deputy director of the FBI who received some of the fiercest of Trump's attacks, was reportedly pushed out of the bureau last week.
Brand, who now oversees the department's civil rights and antitrust divisions, has become embroiled in the scandal, as she is among a number of senior officials who urged Trump to not declassify the four-page memo, citing "grave concerns" about its accuracy.