George Papadopoulos, 31, told the court in Washington DC he was a "patriotic American" who made a mistake by lying.
"He struck me as someone who was validating rumors", Papadopoulos said of his April 2016 meeting with Joseph Mifsud, the mysterious Maltese professor who told him that Russian Federation had a cache of Hillary Clinton's emails. Prosecutors sought a sentence of up to six months in prison.
He has cooperated for more than a year with the probe into Russian interference in the United States presidential election, and possible collusion with the Trump campaign. "A great day for America!" he said, unsuprisingly, in a Tweet.
Mr. Papadopoulos was pictured in March, 2016, sitting at a table with Mr. Trump, then-campaign adviser Jeff Sessions who went on to become U.S. Attorney-Ggeneral, and other foreign policy campaign advisers.
PAPADOPOULOS: My recollection was that the senator was actually enthusiastic about a meeting between the candidate and President Putin.
Papadopoulos was the first person affiliated with the Trump campaign to be indicted, as part of the Mueller probe.
Papadopoulos says it has global implications and that "the truth matters".
Papadopoulos admitted that he lied to FBI investigators when they interviewed him.
In the interview with CNN reporter Jake Tapper, Papadopoulos said that he raised the prospect of Trump and his campaign officials meeting with the Russians.
"The President of the United States hindered this investigation more than George Papadopoulos ever could", Mr. Breen told the judge.
She was responding to a question from ABC News Chief Anchor George Stephanopoulos about her interactions with the special counsel's team, asking, "You were questioned, as well, by Robert Mueller's team and from the start, they suspected you were a Russian agent".
Papadopoulos also sentenced to a fine of $9500, 200 hours of community service and a year of prison conditionally.
"I think everyone was a little paranoid throughout this past year", Papadopoulos said. Although Papadopoulos confirmed that Mifsud told him Russians had "thousands of emails" involving Clinton, he claimed he hadn't yet joined the Trump campaign when they spoke. When they came to light, they triggered the investigation that has loomed over the first two years of Trump's presidency.
He said his client doesn't recall telling anybody connected with the Trump campaign about Mifsud's offer of Clinton dirt.
Papadopoulos's main role in the campaign appears to have been a middleman for invitations from Russian operatives for Trump to visit Moscow and possibly meet with President Vladimir Putin. More accurately, Papadopoulos hemmed and hawed, and finally settled on, "I might have, but I have no recollection of doing so".
For a time, Papadopoulos also looked to be a key informant.