But now he's trying to stage a comeback, embarking upon a forgiveness tour of sorts as he urges the state's voters to give him a second chance.
The disgraced former governor is seeking the House of Representatives seat vacated by Tim Scott after the congressman's appointment to the U.S. Senate. Scott replaced South Carolina Sen. Jim DeMint, who stepped down in December to helm the right-wing Heritage Foundation.
"I’ve experienced how none of us go through life without mistakes," Sanford said in a TV ad released earlier this week in the so-called Palmetto State. "But in their wake, we can learn a lot about grace, a God of second chances, and be the better for it."
Sanford's 21-year marriage ended after his trip to Argentina was discovered and he proceeded to publicly wax poetic about being madly in love with his girlfriend. Sanford is now engaged to marry Marie Belen Chapur.
He was also slapped with an ethics fine for misusing taxpayer dollars, and forced to quit as head of the Republican Governors Association.
If Sanford, the current odds-on-favourite, succeeds in winning the party's nomination, he could very likely face the sister of comic Stephen Colbert, who's running for the Democrats in the same district in the March 19 election.
Considered a dark horse when she first announced her intentions, Elizabeth Colbert Busch, 58, is now in the process of sewing up the Democratic nomination after her main primary opponent dropped out of the race.
She recently won the endorsement of Rep. James Clyburn, the highest-ranking black member of the House of Representatives and the dean of the South Carolina Democratic delegation. Organized labour federations have also given her their stamp of approval.
A Sanford/Colbert-Busch showdown would be an electoral dream come true for the media — and for Colbert himself, a native of Charleston, S.C., who once called the former governor as boring as "a manila envelope glued to a beige wall."
Few had as much fun at Sanford's expense when the governor's lies were exposed in 2009. Prior to Sanford's admission that he'd been in Argentina, Colbert predicted the governor was sustaining himself on the Appalachian Trail "by boring wild game into collapsing at his feet."
"The Appalachian Trail is longer than I thought, and he is a really fast hiker," said Colbert when the truth emerged.
Colbert recently cheered on his sister on Comedy Central's "The Colbert Report."
"As a broadcast journalist, I am obligated to maintain pure objectivity," said Colbert.
"It doesn’t matter that my sister is intelligent, hard-working, compassionate and dedicated to the people of South Carolina. I will not be mentioning any of that on my show.”
Furthermore, he said — in character, of course, as a right-wing buffoon of a pundit —Colbert-Busch's run for Congress as a Democrat is a personal affront to his staunch conservativism.
Out of character, however, Colbert is hosting two fundraisers for his sister later this week — one in South Carolina, the other in New York.
In a recent interview with The Associated Press, Colbert-Busch said she wasn't concerned that her brother's fame was overshadowing her campaign.
"I'm not. I'm so proud of what he is and what he has accomplished," she said. "But when people see what I have done, and they know the work we have done and they know me as a person and a professional, it will be fine."
In an interview earlier this week, meantime, Sanford touted his conservative credentials, saying that voters could trust him to do the right thing in Washington despite his personal failings.
"The reality of our lives is that if we live long enough we are going to fail at something and I absolutely failed at my personal life, in my marriage," he told NBC's "The Today Show."
"But one place I didn’t ever fail was with the taxpayer. If you look at my 20 years in politics, what you’d see is a remarkable consistency in trying to watch out for the taxpayer."