Former Wellington rugby player Losi Filipo has been sentenced to nine months supervision and must attend drug and alcohol assessement programmes.
Filipo, who was 17 at the time, was charged with assaulting two men and two women in central Wellington in October 2015.
His lawyer Noel Sainsbury had successfully argued a conviction could damage his client's rugby career.
Justice Collins said last week Filipo had pleaded guilty after being given an indication he would be discharged without conviction, and that he should have the opportunity to change his plea if he wished.
This morning at the High Court in Wellington he maintained his guilty plea, and was re-sentenced.
Along with nine months supervision he is to attend drug and alcohol assessment programmes and a living without violence programme.
In the October 2015 attack, Filipo and his brother provoked a fight in a Wellington street, during which he punched Gregory Morgan so hard he fell to the ground unconscious.
While Mr Morgan was on the ground Filipo stomped on his head about four times. He was taken to hospital with severe concussion and spent six months off work.
Filipo also punched another man, shoved a woman in the throat and hit another woman on the chin, knocking her to the ground.
Mr Morgan said in September the attack had left him unable to work full-time, because of chronic fatigue and migraines and unable to play rugby. He said said he felt Filipo had only avoided a conviction because of his rugby career.
In court today police lawyer Sally Carter said she accepted there were several mitigating factors but there had to be parity with the sentence given to Filipo's brother.
"Four months' community detention as well as community work and reparation ... Perhaps also some community work [could be] imposed".
Filipo's lawyer Noel Sainsbury said the conviction would affect his client's ability to play professional rugby overseas, and he did not resile from his comments in the district court that a discharge without conviction would be appropriate.
While the consequences for Mr Morgan had been serious, and Filipo did not dispute that, it was concerning that media stories had referred to the assault ending Mr Morgan's rugby career, he said.
Mr Sainsbury referred to a post on Mr Morgan's Facebook page which he said suggested the assault victim's rugby career had not ended solely as a result of the attack.
That Facebook post said: "[I've had] about 15 concussions since 2011, 4 in the last 12 months, which have put me out of work and training for 6 months. I should have stopped 10 concussions ago but choosing to toughen up and carry on with the game I love is now taking an effect on me. I'm only 20 years old. If was to receive another concussion the consequences are unthinkable."
Mr Sainsbury said courts needed to be vigilant about what could be considered "gilding the lily" and it was important that victim impact statements were "scrupulously accurate".
Justice Collins said Filipo's offending was disturbing, and stomping on Gregory Morgan's head could have led to his death.
He set a sentence starting point of two years' jail, but gave Filipo several discounts, including for the fact he was a first offender, the rehabilitation steps he had already taken, the $1000 in reparation he had paid, and his young age.
"There are age-related neurological differences between young people and adults, including being more susceptible to outside influences, including peer pressure," Justice Collins said.
If Filipo continued to receive help and guidance there was every prospect of him being a productive member of the community, he said.
After the hearing Mr Sainsbury said Filipo "was very sorry for what happened and now wants to get on with his life".
Wellington Rugby supported Filipo after the attack but, in September, after the case became public, the club terminated his contract.
Last week, in allowing the appeal, Justice Collins said the injuries Filipo inflicted were grave, and the fact that he was still at school and had no previous convictions at the time of the attack should not have meant he was discharged without conviction.
October 2015 - Losi Filipo, then 17, and his older brother were charged in relation to assaults on two men and two women early on Sunday 11 October 2015. His brother, who had previous convictions, was later convicted, fined and placed on supervision.
15 August 2016 - Filipo discharged without conviction by Judge Bruce Davidson, following a sentencing indication hearing. He was ordered to do community work and pay reparation.
26 September 2016 - Details of the case were aired in the media. Solicitor-General Una Jagose became aware of the case and, exercising her own independent powers, decided it was an appropriate case for her to take a closer look at.
29 September 2016 - Crown Law announced approval had been given for the police to seek leave to appeal Judge Davidson's decision in the High Court and an application to do so had been filed.