Bannon’s state-level charges in New York closely resemble an attempted federal prosecution that ended abruptly, before trial, when Mr Trump pardoned Bannon on his last day in office.
Presidential pardons apply only to federal crimes, not state offences.
He arrived at the Manhattan district attorney’s office shortly after 9am on Thursday. He had acknowledged in a statement on Tuesday that he would be charged soon.
Bannon said earlier that District Attorney Alvin Bragg “has now decided to pursue phoney charges against me 60 days before the midterm election”, accusing the Democratic prosecutor of making him a target because Mr Bannon and his radio show are popular among Mr Trump’s Republican supporters.
He added that federal prosecutors “did the exact same thing in August 2020 to try to take me out of the election”, referring to his arrest months before Mr Trump’s re-election loss.
“This is nothing more than a partisan political weaponisation of the criminal justice system,” he said.
Mr Bragg and New York Attorney General Letitia James planned a 1pm news conference to announce charges against Bannon.
Federal agents pulled Bannon from a luxury yacht off the Connecticut coast and arrested him on charges he pocketed more than $1 million in wall donations.
Prosecutors alleged thousands of investors were tricked into thinking all of their donations would go towards the border wall project, although Bannon instead paid a salary to one campaign official and personal expenses for himself.
Two other men involved in the “We Build the Wall” project pleaded guilty in April. They had been scheduled to be sentenced this week, but that was recently postponed to December.
A third defendant's trial ended in a mistrial in June after jurors said they could not reach a unanimous verdict.
In another case not covered by Mr Trump’s pardon, Bannon was convicted in July on contempt charges for defying a congressional subpoena from the House committee investigating the January 6, 2021, insurrection at the US Capitol.
He is scheduled to be sentenced in October and faces up to two years in federal prison.