Andre Jackie Tau Daniels (39), security officer, who appeared before Judge John Brandts-Giesen in the Queenstown District Court yesterday, admitted assaulting Jesse Stefan Boulay at the Vinyl Underground bar on May 26 last year.
At 4.30am, the victim was crossing the crowded bar after buying drinks when he came into contact with Daniels.
After a verbal exchange, Daniels punched the victim three times in the head, causing him to fall to the floor.
The victim went home, but friends called an ambulance after seeing his injuries and he was treated at Lakes District Hospital.
Daniel's counsel, David Allan, said his client went to the Hamilton police station about a week after the assault, after seeing a post on the police Southern district social media page.
The defendant was "extremely remorseful'', although he believed he had acted in self-defence after being hit by either a glass or bottle.
"It would've been better just to walk away.''
Judge Brandts-Giesen said the attack occurred "without warning''.
The victim, who suffered a traumatic brain injury in a car accident in 2010, suffered bruising, a swollen nose and hematomas.
Alcohol made people "act like lunatics'' when drunk early in the morning, he said.
He convicted Daniels and sentenced him to 12 months' supervision to address alcohol issues and any others identified by his probation officer, and 100 hours' community work.
He was also ordered to pay the victim $1000 for emotional harm.
