Norman Waller, 34, was cleared of murder and two wounding charges at Newcastle upon Tyne Crown Court last week, but was found guilty of causing an affray in the incident last February.
Sentencing Waller, of Low Fell, Gateshead, for affray, the judge, Mr Justice Roch, said that it was right he should go to jail because he knew his actions that night would have serious consequences.
Terry Malone, 24, also of Low Fell, died in hospital five days after being stabbed in the chest with a chisel by Waller as the gang surrounded him and his neighbour's son Peter Fay.
The jury, which last week cleared Mr Fay, a 22-year-old university student, of murder and wounding, took the view that the men acted in self-defence when the gang surrounded them.
Mr Justice Roch, said yesterday that he accepted this was self-defence and he was jailing Waller, director of a double glazing firm and a father-of-two, for the 'evil' of causing an affray which led to Mr Malone's tragic death.
The judge said that grabbing a 15-year-old boy in the gang and threatening to cut off his ears with the chisel was 'bound to lead to serious trouble', as was subsequently approaching the main group and waving the chisel.
'It was inevitable that behaviour would lead to further violence and that you and the man with you would get the worst of it. It was also inevitable, because you had introduced a chisel into the situation, that someone was going to get hurt.' The judge added: 'A jail sentence would also make it clear to others that the law will not permit individuals . . . to take the law into their own hands.'
Earlier, David Robson, for the defence, spoke of residents being 'under siege' from car thieves, vandals and burglars.
'It was against that background that a man of impeccable character, a man of peace, felt such a degree of frustration and threat, not only to himself, but to the respectable little community in which he lived, that he snapped and did something wholly uncharacteristic,' he said.
Waller had lost his home, the future of his eight employees was under threat, and he was in danger of reprisals from prisoners at Durham jail. Mr Robson also handed the judge a petition and letters from former neighbours in Low Fell urging him to show mercy.
During the two-week trial the jury heard how Waller had been plagued by crime. His car and his parents' car had been vandalised outside his home at least six times.
He was forced to move his business 20 miles from Low Fell to Fencehouses, Co Durham, after the premises were set on fire, steel shutters were smashed with an axe, and raiders dug a tunnel into the building during an attempted robbery. The court was told that only three of the 20 homes in the street where Waller lived had escaped the attentions of burglars or car vandals.
After his arrest, Waller said: 'I just snapped. I was at the end of my tether with damage to cars and factories. It's just like mob rule. Nothing and no one seems to be safe from them.'