Upset by a heated exchange with two men walking past, Michael Trevor Royce Collins left his first floor apartment to confront them on the street.
Flanked by his mate Harley Hoodless, Collins armed himself with a crowbar.
Collins later told police he only wanted to "put the wind up" Shannon Finemore and Scott McGillivrey who were walking home in Brisbane's Fortitude Valley on Melbourne Cup night in 2020.
Despite being metres from his residence, Mr Finemore, 37, never got there.
Mr Hoodless allegedly punched him in the head during the confrontation, causing him to fall to the ground.
Mr Finemore never regained consciousness.
Days later he died from injuries caused by the blow, Brisbane Supreme Court was told.
Collins had been arguing on his apartment balcony with his partner about what they should have for dinner when Mr Finemore and Mr McGillivrey were walking past.
A woman told the jury that the two men stopped on the street underneath their balcony and mimicked her then boyfriend Collins with a silly, high pitched voice.
Collins believed the two men were mocking him and there was a "back and forth" over the balcony with Mr Hoodless also yelling out, the court heard.
"That you might think should have been the end of it - it wasn't," crown prosecutor David Finch told the jury.
CCTV footage at the trial showed Collins grab the crowbar from his garage as he walked down from the apartment to the street with Mr Hoodless following the exchange.
Collins told police that he only had the crowbar as a "scare tactic".
"It was a good outcome. I walked around and I saw the shock, horror look on their face," he said in a police interview played in court.
The court heard Collins also told police: "I wasn't going down with the intention of hitting him but ... c***s need to learn that they can't just f'***ing mouth off with no consequences."
Defence barrister Victoria Trafford-Walker said during the confrontation Collins had tried to stop Mr Hoodless, who she claimed was acting on his own accord when he allegedly punched Mr Finemore.
"Going downstairs and grabbing the crowbar is where ... the poor choices (by Collins) ended," she told the jury.
"It went wrong because Harley Hoodless went off on his own."
Moments after the alleged punch, the court heard, Mr Hoodless told a passer-by: "I just f***ed that guy up."
However, Mr Finch told the jury Collins held the crowbar throughout the confrontation and had a common intention with Mr Hoodless to unlawfully assault Mr Finemore and/or Mr McGillivrey.
"Mr Collins had not taken a backward step, he did not quit, he did not retreat. Whatever was said, his actions speak louder than words," he said.
Collins pleaded guilty to going armed to cause fear.
However, he pleaded not guilty to unlawful striking causing death at the trial before Justice Melanie Hindman.
The jury began deliberating on Thursday afternoon.
Collins, 30, will be sentenced at a later date after the jury found him guilty on Monday afternoon.
He has been granted bail on strict conditions.