President Donald Trump issued a pardon to former Tennessee state Sen. Brian Kelsey, just 15 days after that Republican began serving a 21-month prison sentence for a campaign finance conspiracy criminal conviction.

"God used Donald Trump to save me," Kelsey, 47, told CNBC in a phone interview Wednesday, a day after his release from a federal prison camp in Ashland, Kentucky.

"His election saved me from the Biden" Department of Justice, Kelsey said.

Kelsey, a lawyer who lives in Germantown, Tennessee, announced that Trump had given him "a full and unconditional pardon" in a tweet on the social media site X.

He told CNBC that three GOP congressmen from Tennessee, Mark Green, Andy Ogles and Chuck Fleischmann, were among the people working to obtain the pardon.

"I'm thrilled for Brian Kelsey, whose pardon is well-deserved!" Ogles said in a statement. "Biden's DOJ weaponized justice to punish a principled conservative. Trump gets it; he's been there. Time to end this abuse of power!"

Kelsey said, "There have been many friends and family who have provided prayers and outreach on my behalf.

The White House and the DOJ have not issued statements announcing Kelsey's pardon or the reasons for it. CNBC has requested comment from the White House and DOJ.

The U.S. Bureau of Prisons confirmed to CNBC that he was released Tuesday from the Ashland camp due to a pardon.

Presidential pardons void a person's criminal convictions and any related sentence.

Kelsey entered the Ashland prison camp on Feb. 24, a month after the U.S. Supreme Court rejected a petition to hear an appeal in his case, and about a month after he submitted a request for a pardon.

Kelsey said he was surprised that he had to report to prison because "I always felt like God was going to provide a miracle, and he had provided so many before."

He had pleaded guilty in November 2022 to crimes connected to his moving money from his state senatorial campaign account to his ultimately unsuccessful 2016 campaign for Congress.

Months later, he tried to withdraw his guilty plea, but failed in that effort. Yet he remained free for nearly two years while appealing the case.

On Tuesday afternoon, Kelsey said, he was exercising in the camp's yard with other inmates, "just doing burpees," when "the assistant warden called out my name, called me forward and told me the president had pardoned me."

Asked what he planned to do now, Kelsey said, "I'm just going to take the day to thank President Trump and others who supported me, and hug on my wife and kids." Kelsey has twin two-year-old boys, and a five-year-old daughter.

Trump on his first day back in the White House on Jan. 20 pardoned about 1,500 people charged or convicted of crimes relating to the Jan. 6, 2021, riot at the U.S. Capitol by a mob of his supporters.

Trump since then has issued pardons for Ross Ulbricht, who had been serving a life sentence from crimes related to his dark web marketplace Silk Road, and to former Illinois Gov. Rod Blagojevich, who previously served eight years in prison on charges relating to his attempt to sell former President Barack Obama's Senate seat after Obama was elected to the White House.

But it is highly unusual for someone to receive a pardon or sentence commutation so early in their prison term, as Kelsey did.

Elizabeth Oyer, who had been the top pardon attorney at the DOJ, this week said she was fired on Friday after she opposed restoring actor Mel Gibson's rights to carry a gun. Gibson, who is a Trump supporter, lost those rights after he was convicted in 2011 for a domestic violence misdemeanor.

On Tuesday, NBC News reported that the Trump administration was gutting the DOJ's Public Integrity Section, which oversees prosecutions of public officials accused of corruption.

The Public Integrity Section had overseen the prosecution of Kelsey.

Kelsey said that he was targeted for prosecution by the "weaponized Biden DOJ."

"Their real target in my case was to take down Matt Schlapp and the American Conservative Union," Kelsey said.

Schlapp, who is a Trump supporter, is the chairman of the ACU, which sponsors the annual Conservative Political Action Conference, known as CPAC.

"They offered to cut me a deal if I would testify against Matt Schlapp and others at the ACU, and threatened me with a frivolous prosecution if I did not," Kelsey said.

"I told them I did nothing wrong, and neither did anyone else at the ACU, and that's when they brought charges," he said.

Schlapp has never been criminally charged by the DOJ.

After CNBC requested comment from Schlapp, a spokeswoman for CPAC issued a statement that said, CPAC fully supports President Trump using his clemency powers to address politicized prosecutions of the past."

"We are particularly pleased that former Tennessee Senator Brian Kelsey was pardoned yesterday," the spokeswoman said. "Neither CPAC nor Matt Schlapp were ever a target of this investigation. Two people employed at the time were thoroughly investigated over years and not charged or convicted."

"We continue to believe that under President Joe Biden the DOJ was used to persecute political opponents, and prosecutions against Republicans far outweighed those against members of his own party," the statement said.

Kelsey's lawyer Joy Longnecker told CNBC that in his pardon petition to Trump, Kelsey said, "I am innocent, and I need your help."

Longnecker said, "Every day, in courtrooms all across the country, innocent people like Brian plead guilty to crimes they did not commit. That is an unfortunate but undeniable fact."

"In its 2023 report, the [American Bar Association's] Criminal Justice Section's Plea Bargain Task Force acknowledged there was 'substantial evidence' that 'defendants – including innocent defendants – are sometimes impermissibly coerced into taking pleas and surrendering their right to trial.' "

"That is exactly what happened to Brian," Longnecker said. "And that is why Brian's pardon was an appropriate exercise of President Trump's executive power."

Kent Wicker, another attorney for Kelsey, said DOJ prosecutors targeted him for political reasons, "withheld exculpatory evidence, and coerced him into pleading guilty to a crime he did not commit."

"Its own star witness recanted his testimony," said Wicker, who called Kelsey "the ideal pardon candidate."