It ended when the teen threw a punch from behind that knocked the ref unconscious, and caused a large cut to his jaw.
The match official has said he never wants to umpire an American football game again.
Given the seriousness of the event and the "severe" impact it had had on the victim since the judge treated this as the main charge.
However Komene's defence counsel said her clients first experience in prison, having been incarcerated since January this year had served as a "huge lesson".
Furthermore she said her client was remorseful for his actions, which she said were related in part to his use of methamphetamine.
"He is extremely keen to engage in restorative justice," she said. "It's a big thing for a man his age to be willing to front up.
"It's something he's been willing to do since the outset."
She said her client, who was a father, had also enrolled in powerful parenting courses and was on a waiting list for a drug and alcohol course.
She said the young man, who'd lived on the streets since he was 13, had taken strides to turn his life around.
The other charges, related to separate offences were one burglary charge, one male assaults female and three of wilful damage.
He'd also faced charges for breaching his community work and three of failing to answer District Court bail.
Justice Earwaker took Komene's youth and "troubled upbringing" into account when delivering the sentence.
"I've got to hold you accountable for what you have done to the victims and the community.
"The umpire was simply doing his job, and you pummeled him out of the blue."
Komene had his original sentence of 3 years and 6 months reduced due to his guilty plea and remorse at his actions.
He acknowledged family members in attendance as he left the court.
The day after he threw the punch at the ref Komene was also given a lifetime ban from the sport.
At the time of the incident, American Football Auckland (AFA) president Lani Ekepati was reported to have said the official's injuries looked "pretty bad" and he'd needed an MRI to rule out anything more serious.
He said a tough stance was taken against the supporter because it was a "family sport".
"It's not just players involved,you've got families supporting young kids.
"Controlled aggression is always in the game and sideline jurors, supporters, always have their own opinion, but at the end of the day it's up to the club to make sure they control their sideline."
