Greitens, a former Navy SEAL who also touts his past philanthropy at home and abroad, was last on the national political radar when he resigned from office amid multiple scandals. They included campaign finance and sexual assault allegations.
Greitens admitted to an extramarital affair but denied the assault allegations, as well as campaign finance allegations.
And in the intervening years, the assault charges against Greitens were dropped largely owing to alleged misconduct by a key investigator on the case, and an ethics panel found no evidence that Greitens knew about reporting issues from his campaign, which are now settled.
Now the former governor and current Senate candidate, saying he's been "exonerated," is looking to restart his political career during the 2022 midterms.
"Her lead investigators has been charged with seven felonies for perjury and evidence tampering for creating a false case against me," Greitens told Fox News in an interview. Greitens was referring to St. Louis District Attorney Kim Gardner. She was the lead prosecutor in the case against him before later gaining national notoriety for being disqualified from the prosecution of Mark and Patricia McCloskey after touting her prosecution of the gun-toting, Trump-backing suburbanites in campaign emails.
"The good news is that eventually that big wave of leftist lies, it just crashes on the rock of the facts. And the fact is that we've been exonerated," Greitens added. "I know from my time as a boxer that you can lose a round but eventually win the fight. I know from my time as a Navy SEAL that you can lose a battle and eventually win the war."
The next battle in Greitens political career will be the 2022 GOP primary for Blunt's Senate seat.
Among the high-profile Missouri Republicans who already are in the race or may jump into it are Attorney General Eric Schmitt, Rep. Ann Wagner, R-Mo., Rep. Jason Smith, R-Mo., and Rep. Vicky Hartzler, R-Mo.
I'm the MAGA candidate in this race.
Schmitt is the only person besides Greitens who is officially in. He previewed what may be a common line of attack against the former governor during the primary campaign – that he is damaged goods and could fall to a Democrat in the general election. Schmitt emphasized in a statement that he is the person to "fight to preserve President Trump’s America First agenda and keep this seat in safe pro-Trump Republican hands."
But Greitens, at least early in his candidacy, may have more juice when it comes to endorsements from high-profile Trump allies. He's been endorsed by former New York City Mayor Rudy Giuliani, former Interior Secretary Ryan Zinke and commentator Sebastian Gorka.
"I want to defend President Trump's America first policies," Greitens told Fox News. "And I want to protect the people of Missouri from the kind of lunatic policies... that have been pushed by Joe Biden and Nancy Pelosi and Chuck Schumer."
He added: "I'm the MAGA candidate in this race. I'm the front-runner who has the support of so many folks like Rudy Giuliani, like Seb Gorka, like Ryan Zinke, like Victoria Toensing and Joe diGenova, because I've been there through the fights and I'm a fighter and I'm going to fight for the people of Missouri in the U.S. Senate."
Greitens told Fox News that if he is elected he plans to pick up where he left off as governor – as a strong backer of law enforcement, particularly federal agents on the southern border amid a migrant surge at the beginning of the Biden administration.
"As governor, I was always on the front lines supporting our police officers and doing it when it was hard," Greitens said. "I think in the same way the people of Missouri need a senator who's willing to go to the front lines, who's not afraid to stand up for them when things are hard."
"If you look right now at the border crisis that Joe Biden has created, we need to have leaders who are willing to go to the front lines and be there on behalf of and with all of our law enforcement agents on the border who Biden has set up for failure," he continued. "Biden has created a national security crisis. It is a public safety crisis. It is a public health crisis. It is bad for economics."
Greitens also cited his past international charity work, saying that "what Biden has done has created a massive humanitarian crisis that is hurting some of the most vulnerable children in the world."
"It's important that the people know that we carry them in our heart every single day... This border crisis also just exposes the heartlessness of the left," Greitens said. "Keeping kids with learning disabilities out of school for a year is heartless. Allowing murders and violence to explode in our cities is heartless. The consequences of leftist policies have real human consequences. And I think it's important to lead from the front lines with both strength and compassion."
Greitens also told Fox News that he is committed to working toward a balanced budget, protecting the Second Amendment, that he's pro-life and supports "President Trump's ... peace through strength foreign policy."
But if Greitens makes it out of the GOP primary, it's not necessarily a sure thing he will waltz to office in the state that went for Trump by a wide margin in 2020. Missouri elected a Democratic senator as recently as 2012.
That was former Sen. Claire McCaskill, who only lost to Sen. Josh Hawley, R-Mo., by about six percentage points in 2018. Her 2012 win over Republican Todd Akin came after Akin's campaign was plagued with gaffes. Conservative radio host Hugh Hewitt raised the possibility that Greitens' candidacy may risk a repeat of that race.
But Greitens in his interview with Fox News said he's confident that Missourians will back him based on his policies and his support for Trump.
"I think the people of Missouri recognize that the people who are attacked by the left and by the swamp are conservatives and outsiders like President Trump," Greitens said. "That's why they came after me. So, you know, they come after me because I am I'm a threat to the establishment. I'm a threat to the swamp. I'm a threat to the left. And so, of course, they come out and attack us."
The Associated Press contributed to this report.