The Washington DC grand jury is separate from the investigation into the former president’s handling of classified documents at his Mar-a-Lago home after he left the White House.
The subpoena is for both documents and testimony and was sent out in late May, sources told NBC News.
Bannon was convicted in July 2022 on two charges of contempt of Congress for refusing to cooperate with the congressional January 6 committee.
In October, US District Judge Carl Nichols sentenced Bannon to four months in federal prison, but the sentence was suspended while he appeals his conviction.
The former chairman of Breitbart News served in the Trump administration for its first seven months before leaving.
The office of the special counsel and Mr Bannon’s lawyer both declined to comment when NBC News contacted them.
Mr Trump’s team was recently informed that he is a “target” of the Justice Department’s document probe.
It began in early 2022 after National Archives and Records Administration officials discovered more than 100 documents bearing classification markings in a set of 15 boxes of Trump administration records retrieved from Mar-a-Lago.
During that search, special agents discovered 103 documents bearing classification markings, including 18 marked “top secret,” 54 marked “secret,” and 31 marked as “confidential,” including a number of documents that were stored in Mr Trump’s personal office.