Zak Grieve - an Aboriginal man serving life in prison for a murder he was found not to have physically committed - will be eligible for release eight years early after a successful mercy plea.
The 26-year-old was convicted for his role in the 2011 murder of Raffaeli Niceforo in the outback Northern Territory town of Katherine.
Despite a judge finding he wasn't physically present at the murder, Grieve was sentenced to life in prison under the NT's controversial mandatory sentencing laws.
NT Administrator Vicki O'Halloran reduced his non-parole period from 20 to 12 years following a petition from his lawyers and a letter from his mother, Glenice, who wrote she was "gutted" and "frustrated" by the legal process.
Grieve will now be eligible for release in 2023.
His lawyer, Felicity Gerry QC, welcomed the news - despite originally petitioning for immediate release.
"Any success that demonstrates that mandatory sentencing doesn’t work is good success and we’re pleased," said Professor Gerry, who leads a small Indigenous justice and exoneration project.
"It’s not so much of a good result for his mum obviously – his mum would like him home immediately."
Professor Gerry said the decision strengthened the case for abolishing mandatory sentencing laws.
"And for those people affected, they should create a mechanism to make sure that those people can go back before the courts and be properly sentenced by judges," she told NITV News.
In 2011, Grieve was arrested for his role in the murder of Raffaeli Niceforo, who was killed in his Katherine home by Chris Malyschko and Darren Halfpenny.
Malyschko was found to have planned the murder following alleged extreme domestic violence and death threats from Niceforo towards Malyschko's mother.
Grieve's lawyers say he initially agreed to participate in the murder, but later withdrew from the plan.
Despite a judge finding he wasn't present at the killing, Grieve was sentenced to a minimum of 20 years under the NT's mandatory sentencing laws, which set a minimum sentence for certain offences.
The other two men involved in the murder were sentenced to 18 years.
The presiding judge, Dean Mildren, labelled the result an "injustice", the Australian reports.
"It is the fault of the minimum mandatory sentencing provisions, which inevitably bring about injustice," he said at the time.
The case has since become the focus of The Queen and Zak Grieve - an award winning documentary based on the investigation by The Australian.