Sanford announced he would run for Tim Scott's recently vacated House of Representatives seat, representing South Carolina's 1st District. Scott was appointed by Republican Gov. Nikki Haley to fill Republican Senator Jim DeMint's seat. DeMint resigned in December.
Sanford said he intends to run on a platform of bringing fiscal responsibility to Washington.
When Sanford returned from Argentina in 2009, he confessed to his affair in a tearful news conference and later called Maria Belen Chapur his "soul mate." They couple are engaged and plan to marry this summer. His wife divorced him within the year. Sanford later resigned from office.
Sanford represented the 1st District for three terms in the 1990s. Sanford is known for his tight-fisted ways. When first running for governor in 2002, he once boasted of sleeping on a cot in his office to save money and later brought squealing and defecating pigs to the Statehouse to make a point about pork barrel spending in the state budget.
But his fiscal conservatism was also questioned when The Associated Press examined his travel expenses as governor, including an economic development trip to South America in which he had a romantic rendezvous with Chapur.
Before leaving office, Sanford avoided impeachment but was censured by the Legislature over state travel expenses he used for the affair. He also paid what is still the largest ethics fine ever in South Carolina at $70,000.
His tearful confession, though, cost him his marriage to his then-wife, Jenny, who was also his closest political confidant and campaign manager.
She later wrote a tell-all book about their relationship, and flirted with the idea of running for the 1st District seat. But the mother of four boys with Mark Sanford scrapped those plans this week, saying being at home with family was more important than running for Congress.
Gov. Sanford spent his last 18 months in office traveling around the state, asking for forgiveness.
"The apology tour, if you want to call it that, is over. All you can do is say I'm sorry. But at some point, you have to lift up your head and start moving and I'm at that point," he said.
Sanford has the instant name recognition and could, if he gets permission from donors, tap into $1.1 million he has remaining in his gubernatorial campaign fund.
Teddy Turner, the son of media magnate Ted Turner, has said he will seek the GOP nomination in the district. Several state lawmakers have also announced plans to run, although the official filing for the race doesn't open until Friday. The primary is March 19.
South Carolina voters haven't had much of an appetite for political comebacks for officials who make headlines for a faux pas or controversy. Former Lt. Gov. Andre Bauer couldn't overcome his personal troubles with speeding, a plane crash and other controversies to win the governor's office or a congressional seat, and former Gov. David Beasley couldn't shake his support for removing the Confederate flag from the Statehouse dome when he ran for office again.
The Associated Press contributed to this report.
