Foreign policy advisor to President Donald Trump's election campaign, George Papadopoulos goes through security at the US District Court for his sentencing in Washington, DC on September 7, 2018.

George Papadopoulos, the former Trump campaign aide who admitted lying to federal investigators about his contacts during the 2016 presidential election, left a federal prison Friday after serving a 12-day stint.

Papadopoulos was released from an Oxford, Wisconsin, federal prison Friday around 9 a.m. local time. Although he was sentenced to serve 14 days in custody, he was released after a dozen days, having received credit for two days he spent in jail earlier after his arrest in the case.

He now will be free on supervised release for one year. His sentence also requires him to pay a $9,500 fine and complete 200 hours of community service.

The 31-year-old foreign policy aide pleaded guilty in October 2017 to lying to the FBI as part of special counsel Robert Mueller's ongoing probe of Russian interference in the 2016 election and potential coordination between the Trump campaign and the Kremlin.

Papadopoulos had met with professor Joseph Mifsud, who had ties to Russia in early 2016. In late April 2016, Mifsud told Papadopoulos that Russians had "dirt" on Trump's political opponent, former Secretary of State Hillary Clinton, including "thousands of emails," according to the special counsel's court filings.

Papadopoulos' two-week jail time was shaved down because he had already received two days of "jail credit," a spokeswoman for the prison told CNBC, meaning the time he spent in a jail somewhere else before arriving at the Wisconsin prison was applied to that sentence.