He was also given a £7,300 ($9,500) fine and community service.
In requesting that Papadopoulos serve some prison time, government lawyers said he and his wife had participated in media interviews riddled with misstatements.
By lying to investigators, Papadopoulos had made "a calculated exercise of self-interest over the national interest", said Moss.
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While this chapter of the Mueller investigation concludes for Papadopoulos, his testimony and information he provided as part of his plea deal could mean trouble for others in Trump's circle, including Mr. Trump himself.
The Trump campaign adviser who triggered the Russian Federation investigation will find out Friday whether he will be going to prison for lying to the FBI.
Russian Federation has denied US allegations that it interfered in the campaign and President Trump denies campaign collusion.
The Chicago native was a London-based petroleum analyst before he joined the Trump campaign in March 2016 as a volunteer foreign policy adviser.
The sentence was imposed in federal court in Washington.
"While some in the room rebuffed George's offer, Mr Trump nodded with approval and deferred to Mr Sessions, who appeared to like the idea and stated that the campaign should look into it", Papadopoulos claimed in a pre-sentencing statement last week.
He was the first ex-Trump aide arrested in the probe into an alleged Kremlin plot to sway the 2016 U.S. vote.
Federal Bureau of Investigation agents interviewed Papadopoulos in January 2017, and he lied about his April 2016 conversation with Joseph Mifsud, a Maltese professor working in London who had ties to Russian officials. "I don't know him", Trump said.
In addition, they said Papadopoulos did not provide "substantial assistance" and only came clean after he was confronted with his own emails, texts and other evidence.
Papadopoulos further stressed: "I remember him being enthusiastic about a potential meeting between the candidate and President Putin after I raised the question". He admitted to lying about those contacts to Mueller's team, which investigators said led them to miss a chance to interview the professor, Joseph Mifsud.
When Papadopoulos pleaded guilty previous year, he pledged to help the special counsel's office with its investigation.
In hindsight, he said in court, he recognizes that was wrong and "might have harmed the investigation". His attorneys, Mr Breen and Robert Stanley, said their client lied to save his career and to "preserve a perhaps misguided loyalty to his master" - a reference that is not fully explained in court papers.