WASHINGTON — John Demers, the head of the Justice Department’s National Security Division, will step down at the end of next week, according to an email he sent to his staff on Monday, a departure that was arranged months ago but comes amid backlash over investigations into leaks of classified information.
Mr. Demers was the longest-serving Senate-confirmed official from the Trump administration to remain at the Justice Department during the Biden presidency.
“You can probably imagine that I’ve stayed much longer than planned, but long ago I told the new folks that when school was out, I was out,” Mr. Demers, who has school-age children, wrote in the email, a copy of which was obtained by The New York Times. “And that’s the end of next week.”
Mark J. Lesko, the acting top federal prosecutor in Brooklyn, will replace Mr. Demers on an interim basis until the division’s new leader is confirmed by the Senate, according to an official familiar with the matter. President Biden has nominated Matthew G. Olsen, an Uber executive who has served in several national security roles in government, to serve as the head of the National Security Division. His Senate confirmation hearing could happen as soon as next month.
John Carlin, the second in command in the deputy attorney general’s office, had asked Mr. Demers in April to remain at the department, according to the person. Lisa O. Monaco had just been confirmed to serve as the deputy attorney general, and the three officials had a long history of working together on sensitive national security cases.
Mr. Demers asked to leave by summer, and the two men eventually agreed that he would stay on through June 25, the person said.
But Mr. Demers’s departure also comes as Democrats and First Amendment advocates have attacked the Justice Department following revelations that prosecutors supervised by Mr. Demers seized the records of reporters from The New York Times, The Washington Post and CNN and of top House Democrats while investigating leaks of classified information. The department’s inspector general announced an investigation on Friday into the matter.
While it is common for the Justice Department to try to find out who shared classified information with the media, it is highly unusual to secretly gather records from the press and lawmakers. The prosecutors also prevented the lawyers and executives of The Times and CNN from disclosing that records had been taken, even to their newsroom leaders, another highly aggressive step.
Such moves require signoff by the attorney general. But Mr. Demers and his top counterintelligence deputies in the division would typically be briefed and updated on those efforts.
Much of the spotlight on national security cases during Mr. Demers’ three-year run focused instead on the special counsel, Robert S. Mueller, III, who ran the Russia investigation, the Justice Department’s highest profile and politically fraught national security matter.
But Mr. Demers’s ability to skirt controversy ended in recent weeks as the revelations about reporters’ record seizures and the gag orders came to light.
Justice Department officials say that all appropriate approvals were given for those orders, meaning that the attorney general at the time, not Mr. Demers, signed off.
Former Attorney General William P. Barr approved the decision to seize records from CNN and The Washington Post in 2020, people with knowledge of the leak investigations have said. But it is unclear who approved the request for email records from Google that belonged to Times reporters. The request was filed with a court days after Mr. Barr left, though he could have signed off on it before leaving.
A Justice Department spokesman declined last week to identify whether Mr. Barr or his successor, former acting Attorney General Jeffrey A. Rosen, approved that move.
Leak investigators in 2018 also obtained data from Microsoft and Apple that belonged to Democrats on the House Intelligence Committee, including Representatives Adam Schiff and Eric Swalwell, both of California. Mr. Schiff is now the panel’s chairman.
In those instances, the Justice Department also told the technology companies not to inform customers about the subpoenas until recently.
The data was collected and the gag orders were imposed on the tech companies weeks before Mr. Demers was confirmed to lead the National Security Division.
Still, some Democrats demanded answers about what he knew about the leak cases.
Senator Chuck Schumer of New York, the majority leader, called on Mr. Demers on Sunday to testify before Congress.
When Mr. Demers became the head of the National Security Division on Feb. 22, 2018, he was praised by both Democrats and Republicans, who noted that he had worked under administrations of both parties.
The confirmation is his third stint at the department. From 2006, when the National Security Division was created, to 2009, Mr. Demers was part of its leadership team. He had previously worked in the department’s Office of Legal Counsel, essentially the government’s lead legal adviser, and in the office of the deputy attorney general.
He graduated from Harvard Law School, where he and Mr. Carlin were friends and classmates.
As the head of the National Security Division, he will likely best be known for his work to combat the threat of Chinese intellectual property theft and espionage.
When the White House announced Mr. Olsen’s nomination to take over the division, Mr. Demers said in an email to his staff that “Matt is the right person to lead this division,” according to a copy obtained by The Times.
Before joining Uber, Mr. Olsen worked as a federal prosecutor in the U.S. attorney’s office in Washington, served in top roles at the F.B.I. and the National Security Agency and as director of the National Counterterrorism Center during the Obama administration.
Mr. Lesko has served as the acting U.S. attorney for the Eastern District of New York since March, replacing Seth DuCharme. Mr. Lesko was a prosecutor in the district from 2002 to 2009 and returned to the office in 2018.
Nicole Hong contributed reporting from New York.