Sheffield Crown Court heard during a trial how Fahim Hersi, aged 22, of Broomhall, was stabbed in the car park at Cineworld, at Centertainment, in September, 2018.
Noel Ramsey, aged 22, of Nottingham Street, Burngreave, had denied murder but pleaded guilty to manslaughter on Tuesday, after admiting throughout to stabbing Fahim in self-defence.
Ramsey’s friend Layton Morris, aged 22, of Ferrars Road, Tinsley, had denied assisting Ramsey by disposing of the knife near a bin but he also pleaded guilty on Tuesday.
Ramsey received five years and Morris was handed six months in prison.
Ramsey read from a statement in which he apologised to Mr Fahim's family and said: "If I could change back time I would, but I can't," he said. "All I wanted to do that day was enjoy a night out. I didn't want to take someone's life and I ask God for forgiveness."
As he was sent down, Ramsey said: “Love you mum.”