The man who killed teenager Patrick Cronin with a single punch could be out of jail in five years.
More than 100 people packed into a Melbourne courtroom on Friday morning where Andrew William Lee, 34, was sentenced to eight years in prison over Mr Cronin's death.
Lee dramatically changed his plea to a manslaughter charge from not guilty to guilty on the third day of his trial at the Supreme Court in September.
Justice Lex Lasry on Friday ordered Lee to serve a minimum of five years before being eligible for parole.
A small group in the court's public gallery burst into applause once Justice Lasry finished reading his sentencing remarks and had left the bench.
Mr Cronin, 19, suffered fatal head injuries when punched to the side of the head by Lee during a brawl at The Windy Mile hotel in Diamond Creek on the night of April 16 last year.
CCTV footage released by the court shows Lee stepping into the brawl to strike Mr Cronin. The vision was shown to the jury but in black and white, but following Lee's guilty plea, the footage was enhanced to highlight Lee coloured red and Mr Cronin coloured green.
After the brawl, Mr Cronin was also seen in CCTV footage telling friends he had been hit. He and his friends left the hotel about 11.30pm but his condition worsened over the following hours. He died in hospital the next night, from bleeding on the brain.
Justice Lasry said Lee had stood to the side of the bar brawl observing for at least one minute before he struck Mr Cronin, and it would have been obvious the teenager was trying to defuse the situation.
That was an example Lee could have followed. The judge found Lee failed to take heed of the knowledge gained from practising Muay Thai, a form of martial arts, that it only be used for self-defence.
"You should have remained standing and watching, or preferably followed the example of Patrick Cronin and done what you could have to have prevented the fight from continuing," Justice Lasry told the killer.
"It is significant that the one person who suffered the terrible consequences of this incident was the person whose behaviour featured no aggression whatsoever.
"On any view you acted violently and that violent act had a dreadful consequences."
Mr Cronin's family spoke outside the court after the sentence.
Despite living with the "life sentence" over the death of their son and brother, they were relieved to put their 19-month legal ordeal behind them.
Matt Cronin said his son was fatally injured doing what he had been taught to do by his parents - looking after his mates.
"He had a choice that night. He could have thrown a punch, he could he could have added to the violence of the situation but instead he chose to help his mate," Matt Cronin said.
"Andrew Lee, he had exactly the same choice but instead he chose tho throw a coward's punch and that punch killed Pat.
"The sentence that's been given today, it was never going to be enough, we resigned ourselves to that fact a long time ago.
"What Andrew Lee needs to live with is the fact that he killed Pat and he's got to live with that for the rest of his life. That's his life sentence."
Prosecutors initially applied for Justice Lasry to impose a mandatory 10-year minimum jail term under Victoria's one-punch laws, but withdrew the request when they couldn't prove Lee intended to punch Mr Cronin.
Justice Lasry was not satisfied Lee intended to strike Mr Cronin.
Matt Cronin and his wife Robyn said on Friday the one-punch legislation introduced in 2014 was poor and ambiguous, and would never be used unless it was reworked by lawmakers.
"Our most basic understanding, and I am not a lawyer, is that manslaughter is murder without intent," Ms Cronin said.
"And then to be sentenced on a coward's punch, intent is suddenly brought back, so how can it ever be used in that fashion? It has to change."
Matt Cronin earlier told ABC Radio sentencing needed to meet community expectation.
"Let's not forget there's really only one victim and that's Pat," he said.
"Pat hasn't had a voice since April 16 so we're his voice and in standing up for our son we just feel that the way the system works is we don't have anyone in our corner."
Mr Cronin said he and his wife had had many meetings with the Office of Public Prosecutions, and most "have ended in tears".
The Cronin family and their supporters planned to get together on Friday night to remember the life of the promising young footballer and aspiring physiotherapist.
"Nineteen months ago a rusty dagger was thrust into our hearts and that dagger's been sitting there," Matt Cronin said.
"Today we're able to pull that dagger out but there's still some rust there. There's a lot of healing, there's a hole in our hearts and we need to get that to heal."
Lee, a former rigger and married father of a young son, sought forgiveness from the Cronins at his plea hearing last month in a letter read to the court.
Judge Lasry found Lee was remorseful, never intended to harm Mr Cronin, had gained insight and had good prospects for rehabilitation. About 25 friends and family were in court supporting Lee.
He showed no emotion when sentenced or led away.