FBI deputy director Andrew McCabe, a frequent target of President Donald Trump's criticism who led the bureau for months last year following the firing of James Comey, is leaving his position.
Today's announcement came ahead of a previously planned retirement this spring.
Mr McCabe had been widely expected to retire upon his eligibility date, but his departure from the FBI's number two slot is effective from Monday with the deputy director granted what was termed "terminal leave".
Mr McCabe has been repeatedly attacked by Mr Trump since the autumn of 2016, when it was revealed that his wife had accepted campaign contributions from the political action committee of Virginia governor Terry McAuliffe, a close Hillary Clinton ally, during a failed state senate run.
Mr McCabe became deputy director in 2016 following earlier jobs running the FBI's Washington field office and serving as head of its national security branch.