The 70-year-old former NFL star and actor was freed from Lovelock Correctional Center just after midnight (3:08 a.m. ET) "in an effort to ensure public safety and reduce the potential for incident," the Nevada Corrections Department said.
A short video showing his first steps outside was also released on the department's Facebook page.
Simpson is expected to remain in Nevada for the immediate future; Florida and California, where he has lived in the past, did not receive requests for transfer before his release, officials said.
And Florida's attorney general said the Sunshine State didn't want him.
"The specter of his residing in comfort in Florida should not be an option," Attorney General Pam Bondi said in a statement Friday. "Our state should not become a country club for this convicted criminal."
Simpson lost his home near Miami to foreclosure in 2012. But two of his children, Justin and Sydney, also live in Florida.
His longtime friend Tom Scotto told NBC News last week that Simpson was looking forward to playing golf, seeing old friends and spending time with family.
One thing he's not relishing: renewed attention on allegations he killed his ex-wife, Nicole Brown, and her friend Ron Goldman in 1994.
"I've done my time," he said. "I'd just like to get back to my family and friends."
In Nevada, parolees typically report to their parole officer as soon as they are released and must submit a written report each month.
They can't associate with ex-cons and must submit to searches of their vehicle or residence. They can't have any kind of weapon — and booze is restricted, with a Breathalyzer result higher than .10 considered a parole violation.
Simpson has no plans to work, Scotto said. That's because any money he makes outside his $25,000-a-month NFL pension can be seized by the Brown and Goldman families, who have judgments from the civil case.
J. David Scott, the attorney for Fred Goldman, said that with interest, the amount Simpson owes to all parties has ballooned to about $140 million.
"He can retire from the world like J.D. Salinger and disappear and live off his pension or he can seek to monetize his newfound fame and go out and attempt to enter memorabilia field or do other things," Scott said.
In the latter case, the attorney said, he's ready to go after every cent Simpson makes. "I view them as fun challenges," he said.
The civil verdict against Simpson wasn't considered by the Nevada parole board. The board also said it didn't consider his 1989 misdemeanor domestic violence conviction because it wasn't listed in a FBI database.
Lawyer Gloria Allred, who once represented Nicole Brown's family, has teamed up with a Nevada legislator to push a bill that would require the board to consider an inmate's domestic violence history before approving release.
If that becomes law, it wouldn't affect Simpson. But Allred said it doesn't mean he can run from his past.
"Mr. Simpson can smile and try to charm those who listen to him, but he will never be able to remove that stain and the legal history and how many people he has hurt in his life because of his criminal conduct," she said.
Tracy Connor is a senior writer for NBC News. She started this role in December, 2012. Connor is responsible for reporting and writing breaking news, features and enterprise stories for NBCNews.com. Connor joined NBC News from the New York Daily News, where she was a senior writer covering a broad range of news and supervising the health and immigration beats. Prior to that she was an assistant city editor who oversaw breaking news and the courts and entertainment beats.
Earlier, Connor was a staff writer at the New York Post, United Press International and Brooklyn Paper Publications.
Connor has won numerous awards from journalism organizations including the Deadline Club and the New York Press Club.
She lives in Brooklyn, N.Y.
Andrew Blankstein is an investigative reporter for NBC News. He covers the Western United States, specializing in crime, courts and homeland security.