Renata punched the promising water polo player in the head while out in the Fortitude Valley nightclub district on January 3, 2016.
The 18-year-old suffered massive brain trauma, with his family making the heartbreaking decision to turn off his life support on January 5.
Before the sentence was handed down, the court heard victim impact statements from Cole Miller's parents describing the "nightmare" of losing their beloved son.
The talented water polo player's father Steven said his youngest son was a "kid with a dream" and his death had thrown the family into "utter turmoil".
He said Cole's life was "violently cut short" in an act that marked the start of a "nightmare" for his loved ones and friends.
"(It's) a nightmare that no one should have to endure," Miller told the court.
"It's been a long 20 months since then (and) I know my children suffer everyday."
"(The) tragic loss of their brother ... is a burden they will carry forever."
At times dabbing his eyes with a tissue, Mr Miller described lying awake at night listening to his wife Mary-Leigh cry.
He then read his wife's statement in which she described having to take anti- depressants and sleeping tablets to cope with the devastation of her loss.
She said she was engulfed by grief whenever left alone and remembered her son as a beautiful, quiet and gentle young man.
Renata appeared distressed in the dock as he listened to the heart-wrenching statements, later making his own apology to the court.
"From the very bottom of my heart, I am truly sorry," he said.
It comes after Renata's co-accused, Daniel Maxwell, walked from court in August after being handed an 18-month suspended sentence for starting the fight that led to Miller's death.
Maxwell has since been deported to New Zealand.
Renata's more than 600 days in pre-sentence custody were declared as time already served.
- AAP
