Steve Bannon, a long-time ally of former US President Donald Trump, was sentenced to serve four months behind bars on Friday, after defying a subpoena from the committee investigating the storming of the US Capitol in 2021.
US District Judge Carl Nichols allowed Bannon to stay free pending appeal, a potentially lengthy process.
He also imposed a fine of $6,500 (€6,590) as part of the sentence.
Bannon has denied any criminal wrongdoing.
The former Trump aid was convicted in July for two counts of contempt of Congress: one for refusing to give testimony and the other for not providing documents.
Nichols handed down the sentence after saying the law was clear that contempt of Congress is subject to a mandatory minimum sentence of at least one month in prison.
"Today was my judgement day by the judge," Bannon told reporters immediately following the sentencing. "We will have a vigorous appeal."
Bannon’s lawyers had argued the judge could have sentenced him to probation instead. Prosecutors had asked for Bannon to be sent to jail for six months.
“In my view, Mr. Bannon has not taken responsibility for his actions,” Nichols said before he imposed the sentence. “Others must be deterred from committing similar crimes.”
The House panel had sought Bannon’s testimony over his involvement in Trump’s efforts to overturn the 2020 presidential election. Bannon has yet to testify or provide any documents to the committee.
Prosecutors argued Bannon, 68, deserved the longer sentence because he had pursued a “bad faith strategy” and his public statements disparaging the committee itself made it clear he wanted to undermine their effort to get to the bottom of the violent riot.
“He chose to hide behind fabricated claims of executive privilege and advice of counsel to thumb his nose at Congress,” said prosecutor J.P. Cooney.
“It must be made clear to the public, to the citizens, that no one is above the law," he said.
The defence, meanwhile, said he wasn’t acting in bad faith.
Many other former White House aides have testified with only their own counsel.
Bannon had been fired from the White House in 2017 and was a private citizen when he was consulting with the then-president before the riot.
Before the judge handed down the sentence, Bannon’s lawyer, David Schoen, gave an impassioned argument railing against the committee and saying Bannon had simply done was his lawyer told him to do under Trump’s executive privilege objections.
“Quite frankly, Mr. Bannon should make no apology. No American should make any apology for the manner in which Mr. Bannon proceeded in this case,” he said.
As he walked into court on Friday, Bannon told reporters, “this illegitimate regime, their judgment day is on 8 November when the Biden administration ends.”
Bannon did not speak during the hearing, saying only, “my lawyers have spoken for me, your honour.”
He is also facing separate money laundering, fraud, and conspiracy charges in New York related to allegedly cheating donors to that campaign that wanted to build a wall between the US and Mexico.
Bannon has pleaded not guilty.