Russian Federation investigation to be sentenced.
He was also the first to detail a member of the Trump campaign having knowledge of the Russian efforts to meddle while it was going on.
"I made a terrible mistake, but I am a good man", he said Friday at his sentencing hearing in federal court in Washington.
Papadopoulos acknowledged that he had lied to investigators about contacts with a Kremlin-linked professor who informed him in April 2016 that the Russians had "dirt" on Hillary Clinton and "thousands of emails".
Papadopoulos learned his fate Friday in federal court in Washington.
US District Judge Randolph Moss sentenced foreign policy aide George Papadopoulos to 14 days, noting that he "lied in an investigation that was important to national security".
They said Papadopoulos's initial lies hindered investigators' ability to effectively question, challenge or detain Joseph Mifsud, the London professor who had contacted him.
Moss noted that many similar cases resulted in probation but said he imposed a sentence of incarceration partly to send a message to the public that they can't lie to the Federal Bureau of Investigation.
"The president of the United States hindered this investigation more than George Papadopoulos ever could", Breen said.
In today's sentencing, Papadopoulos was also handed a fine of $9,500 (£7.500), 12 months of supervised release and 200 hours of community service.
Out of the 35 people and entities so far charged, Papadopoulos is one of five who have pleaded guilty and the second to be sentenced.
George Papadopoulos, former campaign adviser for Donald Trump, arrives for sentencing with his wife Simona Mangiante Papadopoulos.
He later attempted to use his links to the professor and Russian nationals to attempt to set up a meeting between Trump and Russian President Vladimir Putin. "I made a awful mistake but I am a good man", he said.
In his pre-sentencing statement, Papadopoulos admitted lying to FBI investigators in January 2017 but said it had been out of a desire to protect his career and a naive loyalty to the Trump administration.
"I saw him sitting in one picture at a table with me, that's the only thing I know about him", Trump said, referring to a widely circulated photo of Papadopoulos in a meeting with Trump and several other advisers.
Papadopoulos was the key to discovering that, the government says.
Mr. Sessions has previously testified to Congress that he pushed back against the proposal, but the memo filed by Mr. Papadopoulos's lawyers contradicts Mr. Sessions' account, saying that both Mr. Trump and Mr. Sessions appeared receptive to the idea.
"We don't talk politics", he said.
Before the sentence was read, Papadopoulos' defense attorney, Thomas Breen, pointed fingers at Trump.
Van der Zwaan, a Dutch lawyer who worked with Manafort and Gates, was also convicted of lying to prosecutors.