Peterson posted a $300,000 bond, but he must remain under house arrest with electronic monitoring. He also surrendered his passport.
"I have waited over eight years ... 2,988 days as a matter of fact; I counted for an opportunity to have a retrial," he said Thursday. "I want to thank all the people that have supported me from all over the world... its impossible for me to express my gratitude, what I want to do now is spend time with my family and with my children."
Peterson, 68, gained his freedom Wednesday after Superior Court Judge Orlando Hudson ruled a SBI analyst misled jurors about the strength of bloodstain evidence in his 2003 trial.
He was convicted of first-degree murder in the 2001 death of Kathleen Peterson, who was found at the bottom of a bloody staircase in the couple's mansion. Peterson has maintained his wife died in an accidental fall after drinking alcohol and taking Valium.
"I think it's a very sad thing when an expert called by the state of North Carolina, who's supposed to be impartial and present technical information to help the jury, becomes an advocate who misrepresents facts and conclusions," said Peterson's attorney, David Rudolf, who also represented Peterson in his 2003 trial.
Judge Hudson ruled that former State Bureau of Investigation agent Duane Deaver misled jurors when he testified that his analysis of blood spatter showed beyond any doubt that Kathleen Peterson died after being struck by her husband three times with a blunt object.
The state agency fired Deaver in January after an independent audit found problems in 34 cases where he either misreported test results, withheld results that could have helped the defendant or overstated the strength of the evidence to help prosecutors. In one of those cases, a man spent more than 17 years in prison before being released after a state innocence panel exonerated him.
Deaver was a crucial witness at Peterson's trial, which was carried live on cable television and became a documentary film and a made-for-TV movie.
Deaver's attorney Phillip Isely said in a statement that his client did not lie.
"We respectfully disagree with Judge Hudson's belief that our client committed perjury. My client, Duane Deaver, did not commit perjury or mislead the court in anyway," he said.
But over the last week, Peterson's defense presented witnesses to cast doubt on Deaver's credibility, including three of the agent's former colleagues. Nationally recognized experts in bloodstain pattern analysis also testified that Deaver used antiquated techniques and gave opinions before the jury that could not justified through a scientific examination of the evidence.
The defense also showed that Deaver greatly exaggerated his level of expertise when he was certified to provide expert testimony and was untruthful about working prior crime scenes where someone died in a suspected fall.
"You have a right not to be tried with fabricated evidence," Rudolf told the judge. "There is no way to sugarcoat it. Deaver lied to this court and this jury multiple times."
Durham District Attorney Tracey Cline conceded that Deaver's methods were flawed. However, she insisted the discredited analyst had still reached the correct conclusions.
"He's guilty as hell," she said of Peterson, citing autopsy results and other evidence in the case.
Cline said she Peterson will be tried again. However, she said she has no intention of handling the case.
If the case does go to a second trial, the prosecution will not be able to use much of the evidence that helped win a conviction because an appeals court ruled a search warrant issued during the investigation was improper. Police also never found the blunt object.
Hudson, the judge at the 2003 trial, openly questioned whether Cline's office could still win a conviction.
"You've got no witnesses," he said. "You've got no confession."
"I don't think a circumstantial case is a bad case," she said.
Peterson will stay at a friend's home until his retrial - which has not yet been scheduled.
"He's not going to be going out and playing 18 holes of golf or anything crazy like that," Peterson's lawyer Kerry Sutton said.
Instead, he and his lawyer will be planning the next stage of this high profile case.
"It doesn't really always come down to what happened or what should happen or what could happen .. what may happen all it really comes down to is what can the state prove," Sutton said.
Peterson's novels include the 1990 "A Time of War," an in-the-trenches look at the war, and a 1995 sequel, "A Bitter Peace." Peterson was also a regular columnist for the Durham Herald-Sun and mounted an unsuccessful campaign to be the city's mayor.
Clayton Peterson, one of Peterson's sons, said his family is looking forward to a second trial. He offered up his house to help secure his father's bond.
"We are confident he will be found innocent," Clayton Peterson said.
Kathleen Peterson's daughter Caitlin Atwater gave ABC11 a statement Thursday: "My thoughts, as always, are focused on the loss of my Mom, a wonderful, beautiful, and vibrant person who tragically lost her life ten years ago last Friday." She said "She meant much to Durham and everything to me. Michael Peterson is still charged with her murder and this is still in the hands of the justice system."
Meanwhile, Kathleen Peterson's family says they stand by the original conviction and believe the same will happen again.