Jack Whomes was jailed for life in 1998 alongside Michael Steele for the murders of Tony Tucker, Pat Tate, and Craig Rolfe.
The three men were found shot dead in a Range Rover in Rettendon, near Chelmsford, Essex, in 1995.
The killings took place after a row over a drug deal, prosecutors said, and the case later inspired the 2000 film Essex Boys starring Sean Bean.
A Parole Board panel decided 59-year-old Whomes – who still protests his innocence – was suitable for release.
He must comply with strict licence conditions, including living at an agreed address, to provide details of what vehicles he is using, to comply with restrictions on contacting certain people, his activities, movements and using technology.
A Parole Board spokesman said: “We can confirm that a panel of the Parole Board has directed the release of Jack Whomes following an oral hearing.”
According to a document detailing the decision, at the time of his offending Whomes had a “willingness to resort to violence and to use weapons”, had “antisocial friends”, acted on the “spur of the moment without thinking adequately about the consequences” and had difficulties with money and holding down a job.
He still maintains his innocence and “as a result little or no work had been completed to address offending behaviour”, according to the document.
But it added he had worked on his education and employment skills and, since being in an open prison, “there had been no concerns reported about his behaviour, which the panel was told had been exemplary.”
Whomes first became eligible for parole in May and the decision was made after his second review by the Parole Board.
It comes after he was recommended to be transferred to an open prison in 2019 and he has already had periods of temporary release.
The Parole Board spokesman added: “Parole Board decisions are solely focused on what risk a prisoner could represent to the public if released and whether that risk is manageable in the community.
“The panel carefully examined a whole range of evidence, including details of the original crime, and any evidence of behaviour change, as well as understood the harm done and impact the crime has had on the victims.
“Parole reviews are undertaken thoroughly and with extreme care. Protecting the public is our number one priority.”