Sanford told the newspaper this morning that he didn't know why his staff said he was on the Appalachian Trail but that "in fairness to his staff," he had told them he might do that.
"I would also apologize to my staff. ... I let them down by creating a fiction about where I was going," Sanford said in the press conference, and added that he did not ask any of his employees to cover up the affair.
A U.S. Embassy official in Argentina told ABC News the embassy had "absolutely no idea" that Sanford was in the country, adding that this comes "from out of left field. It would be extremely odd that a U.S. governor would not check in with the embassy."
But a Department of State spokesperson said if Sanford decided to travel as a private citizen, the department would not have to be informed.
Earlier this week, Sanford's family and staff said they were not concerned. His office said in a statement that it was not uncommon for the governor to "go out of pocket for a few days at a time to clear his head."
Jenny Sanford told The Associated Press Monday that the governor was "writing something and wanted some space to get away from the kids."
But what ignited national curiosity was that Sanford's security agents were unaware of his whereabouts and Lt. Gov. Andre Bauer -- who would be in charge in the governor's absence -- said he didn't even know Sanford was going away.
This morning Sanford flew back to Atlanta rather than to Columbia, S.C., to avoid a media stampede.
Sanford's communication director said Tuesday, "It would be fair to say the governor was somewhat taken aback by all the interest this trip has gotten."
Sanford recently emerged as an outspoken opponent to President Obama's $787 billion stimulus plan, becoming the only governor to reject the federal stimulus money.
Instead of using the $700 million in stimulus money to fund projects, Sanford argued that the money instead be used to pay down South Carolina's deficit, an argument rejected by the federal government. He also lost in court when South Carolina's Supreme Court ruled that the governor had to accept the money.
In an ABC News interview earlier this month, Sanford said the Supreme Court decision did not come as a surprise, but that he still disagreed with the federal government's assessment that the stimulus will help boost his state's economy.
"The problem was if you spent all the stimulus money in our state, what it meant was that you dig for yourself about a billion dollar financial hole 24 months from now, and then the question was, and then what? I think it's financially reckless to embark on a journey to put you about a billion dollars in the hole in 24 months," he said. "The other part of the objection was the reform and restructuring that won't take place. What this amount of federal money allows you to do is to pay for all the changes that would've been made under more austere financial conditions."
"What this medicine out of Washington does is in fact weaken our state in the long run," he said.
Additionally, the South Carolina Legislature last week overturned all 10 of Sanford's vetoes on the stimulus.
While he may like to keep under the radar, there were some questions -- before the news of the affair -- that Sanford may consider a run for the presidency in 2012. The governor told ABC News that right now, "it's not my focus, it's not my aim, it's not my intent," but added "you never say never."
Those ambitions, some say, may be dashed for now.