His case was the first to detail a member of the Trump campaign having knowledge of Russian efforts to interfere in the 2016 presidential election while it was ongoing.
He was handed a 14-day jail term as he told a court in Washington: "In January 2017, I made a bad mistake for which I paid dearly, I am ashamed".
He then pleaded guilty to lying to the Federal Bureau of Investigation about the his contacts with Joseph Mifsud, a London-based professor with connections to high-ranking Russian officials, who told him in late April 2016 that Russians had "dirt" on Hillary Clinton.
His lies about the timing of his encounter with the professor, including the false claim that it came before he'd joined the campaign, prevented investigators from effectively questioning Mifsud when he was in Washington in February 2017, prosecutors said in a court filing.
He is the first former campaign aide to be sentenced in special counsel Robert Mueller's Russian Federation investigation. "An investigator involved in our efforts to serve him was told Mifsud might be deceased", DNC spokeswoman Adrienne Watson said.
The punishment was far less than the maximum six-month sentence sought by the government but more than the probation that Papadopoulos and his lawyers had asked for.
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The president weighed in shortly after the sentence was handed down, scoffing in a tweet at the length and making an apparent reference to the cost of Mueller's investigation.
Papadopoulos told CNN in an interview aired on Friday that Mr Trump "gave me a sort of a nod" and "wasn't committed either way" about the idea of a meeting with the Russian leader.
Memos authored by House Republicans and Democrats, now declassified, also show information about Papadopoulos' contacts with Russian intermediaries triggered the FBI's counterintelligence investigation in July 2016 into potential coordination between Russia and the Trump campaign.
"While its true that George made some political rookie mistakes on the campaign and afterwards it's important to remember that he's the victim here", Gordon said. He recalled how he and attorney Robert Stanley and Papadopoulos visited the Federal Bureau of Investigation office in Chicago months ago and noticed the photos of Attorney General Jeff Sessions and Trump hanging on the lobby wall. Overall, they say Papadopoulos did not provide "substantial assistance". Jeff Sessions "appeared to also like the idea and stated that the campaign should look into it".
"We were hoping for no jail time but two weeks is OK", Maria Stamatopoulos said.
Papadopoulos' attorney asked for probation.
Van der Zwaan was sentenced to 30 days in a Pennsylvania prison and received a $20,000 fine.