He was granted patrol in July and according to a Nevada prison official was released today.
The 70-year-old American football star has spent nine years in jail after being caged for a 2008 armed robbery.
He was convicted for 33 years with a minimum of nine years without parole.
Simpson served his sentence at the Lovelock Correctional Center in Lovelock, Nevada.
In July, Simpson begged for his freedom when he appeared in front of the parole board.

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He said: “I am sorry things turned out the way they did. I had no intention to cause a crime.
“I just want to get back to my family and friends. I thought I was a good guy. I’ve had a few problems with fidelity.
“But I’ve always thought I’ve been pretty good with people and I’ve spent a conflict-free life.
“I’m a pretty straight shooter. I’ve always tried to be a good soldier. I have no problem.”
Simpson, known as The Juice, was acquitted of the 1994 killings of ex-wife Nicole Brown Simpson and Ronald Goldman.
More to follow…