Reynaldo B. Regis, 53, of Fort Washington, Maryland, worked for the CIA from August 2006 through November 2016, said prosecutors for the U.S. Attorney's Office in the Eastern District of Virginia.
They alleged that Regis improperly searched classified databases and copied the information into personal notebooks, which he then took to his house.
During a search of his home, FBI agents uncovered 60 notebooks, which prosecutors say contained "highly sensitive intelligence reports."
"Mr. Regis is a decent man who has served his country for many years with distinction," his attorney, John Zwerling, said by telephone.
"He made a mistake - a serious mistake. He has acknowledged it, he has pled guilty, he has accepted responsibility and he is now a convicted felon because of this mistake. He needs and wants to do what he can to move on with his life."
It was not immediately clear why Regis took the information, nor whether or not he intended to share it with anyone.
When law enforcement agents interviewed Regis, he denied copying the information from the classified databases.
He will be sentenced on Sept. 21.
While he could face up to five years in prison, the sentences imposed under U.S. guidelines are typically less than the maximum.
Comment: Maybe Regis saw that Hillary and Comey got away with mishandling classified information and assumed it was OK.