The Parole Board made their decision after holding a hearing over video link with Yousef Khan, now 20.
Khan was just 14 when he attacked his teacher.
They made their decision despite admitting professional witnesses “differed in their recommendations concerning his suitability for release.”
His victim, Vincent Uzomah, 56, told The Mirror he is worried about his family’s safety.
The teacher thought he was dying after a 14 year old pupil stabbed him in the stomach during a lesson six years ago.
The “arrogant” teen from Bradford struck after he was told off about his mobile phone.
The youth used the N-word just before plunging the knife into Mr Uzomah.
As he lay bleeding, on his classroom floor, in June 2015, Dr Uzomah prepared a final message for his wife and three children.
The teen later boasted of what he had done on Facebook, writing: “The m * f****r, getin funny so I stuck the blade straight in his tummy.” It was liked by 69 of his friends, a court heard at the time.
His attacker later admitted wounding with intent to cause grievous bodily harm and was given an ‘extended’ 11 year sentence. He was due for release in June 2021.
But the teacher he attacked, who now works as a lecturer with more mature students, says he fears for his family.
“The physical and mental scars will never go. I still feel pain on my stomach and I still dream about it and have flashbacks,” he told The Mirror.
“The right side of my stomach is bigger than the other side and the large scar runs from the top to the bottom of my tummy. It’s there as a constant reminder.
“But that’s something I have to live with. It’s an experience that will never go away.
“I was expecting him to be released but I do fear for my family. They do not know who is walking next to them.
“I just hope he is a changed man but I am worried about what he will do because I believe he has no remorse.
“He could have been released after three years on good behaviour but wasn’t.
“If he comes out and starts meeting with the same people there could be the some problems.
“We are trying to move on with our lives and trying to forget it. But the damage is still there.”
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The Parole Board said in their summary when the boy, who could not be named for legal reasons until he turned 18, committed the crime he was living a “chaotic” life and was taking drugs with nowhere suitable to live.
They noted he “was loyal to people who lived the same negative, criminal lifestyle, which included offending for financial gain and being willing to use violence, including using weapons, to get what they wanted.
“He had little education and therefore no prospects of a decent job.
“He did not cope well with life’s problems, struggled to manage his emotions, held grudges against those he believed had offended him and behaved impulsively, without thinking about the consequences of his actions.”
But they decided they were “satisfied” Khan could now be released after hearing he had taken part in “accredited programmes” to address his offending , the impact of his crime on his victim and his thoughts about violence.
But he must live in specific accommodation, be of good behaviour, abide by an exclusion zone preventing him from going anywhere near the victim and be subject to drug testing.
It is believed he could be released in May to the selected accommodation.