Bannon, 68, was convicted in July on two counts - for refusing to provide either testimony or documents to a committee probing the 6 January 2021 riot at the US Capitol.
In addition to the jail time, Bannon must also now pay a fine of $6,500 (£5,833).
He has denied any criminal wrongdoing.
Judge Carl Nichols said that Bannon would be released for the time being, while any appeal to sentence is resolved.
Bannon was a key player in Donald Trump's successful 2016 election campaign and later took the role of chief strategist at the White House. He left that position following a violent far-right rally in Charlottesville, Virginia in August 2017. Even after his departure, the combative and controversial podcaster was considered a top ally of Mr Trump.
The relationship between the two men, however, has occasionally been complicated. Following the 2018 publication of the book "Fire and Fury" by journalist Michael Wolff - which attributed a number of controversial statements to Bannon - Mr Trump disavowed him, saying that he "cried when he got fired and begged for his job" and referred to him as "Sloppy Steve".
In the wake of the 6 January 2021 riot, Bannon did not comply with a summons - known as a subpoena - seeking testimony and records about efforts to overturn the outcome of the 2020 presidential election, as well as about the events that lead up to the storming of Congress.
Prosecutor JP Cooney said on Friday that Mr Bannon "hid behind a fabricated claim of executive privilege to thumb his nose at Congress".
"It must be made clear to the public ....that no one is above the law," Mr Cooney added.
Ahead of Bannon's sentencing, prosecutors alleged that this refusal to comply "exacerbated the assault on the Capitol" and that he "continues to unlawfully withhold documents and testimony that stand to help the committee's authorised investigation to get to the bottom of what led to January 6."
Bannon's attorneys have characterised the case as politically motivated and said that he was attempting to negotiate - rather than ignore - the subpoenas. They added that he believed the deadlines in the summons were flexible.
Judge Nichols partly agreed, saying that it appeared that Bannon was following legal advice and that he "did not completely ignore the subpoena or fail to engage with the committee at all".
Defence attorney David Schoen - who represented Mr Trump in his second impeachment trial at the US Senate - said that Bannon was acting "on principle". He also accused prosecutors of being "in zeal" to make Bannon "their trophy".
"Quite frankly, Mr Bannon should make no apology," Mr Schoen said. "There is nothing here to deter. There is nothing here to punish."
In their own sentencing memorandum, the defence said their client should be sentenced to probation only and stated that contempt of Congress charges are rare. Two other senior Trump administration officials, Chief of Staff Mark Meadows and his deputy, Dan Scavino Jr, were not charged after ignoring committee subpoenas.
In a separate case, Bannon is also facing separate fraud, conspiracy and money laundering charges in New York after being accused of cheating donors to a fundraiser aimed at helping Mr Trump build a wall at the US-Mexico border.
He previously faced federal charges over the same allegations before being pardoned by Mr Trump.