Harold Martin was charged on Wednesday, according to a report in The New York Times.
According to a report in The Intercept, he was arrested at his home in suburban Maryland on 27 August.
Whistleblower Edward Snowden also worked for Booz Allen Hamilton before he disappeared in 2013 and surfaced in Hong Kong. He is now in Moscow.
This included information classified as top secret and sensitive compartmented information. The investigators also located government property valued at more than US$1000, which Martin is alleged to have pilfered.
According to the affidavit of the arrest, filed in the name of special agent Jeremy Bucalo, Martin had a top security clearance and was able to access government property that he was not allowed to remove from his place of work without permission.
Among the materials recovered from his home when he was arrested were digital information stored on different devices and removable digital media.
The affidavit said among the classified documents found at Martin's home, six appeared to contain sensitive intelligence data; they were dated sometime in 2014.
It further said that these documents were produced through sensitive government sources, methods and capabilities which were critical to a number of national security issues. Disclosure would reveal the sources, methods and capabilities, it alleged.
Bucalo said the relevant government authorities had determined that these documents could be classified as top secret, and making them public would cause "exceptionally grave damage" to the national security of the US.
Martin apparently confessed to the investigators, during an interrogation which he agreed to, that he took documents and digital files from his workplace to his home, and also kept them in his car, though he knew they were classified.
His home, which is in Glen Burnie in suburban Maryland, has been blurred out on Google's Street View, The Intercept said, adding that it was unknown whether this had been requested by the Martins or a third party.