Lee Bevan tried to shift all the blame for the fatal attack on Brett Carpenter on to his brother Danny.
He tried to portray himself as a victim throughout and told the jury he was terrified of his brother.
He told the jury that he had suffered a string of violent attacks at his brother's hands when growing up.
Lee Bevan said he had an unhappy childhood and was passed from one children's home to the next.
But he said he preferred being in care rather than living with his mother who bullied and picked on him.
In the 1990s he racked up criminal convictions for violence.
On his record are offences of assault occasioning actual bodily harm, battery and assault with intent to resist arrest.
At the time of the attack on Mr Carpenter he had just broken up with his long-term girlfriend with whom he had two children.
The 35-year-old regularly visited his brother's home in Highfield Road, Landport, Portsmouth to drink and smoke cannabis because he hated the small one-bedroom flat where he lived in London Road.
On the day of the murder he had drunk seven or eight cans of Stella Artois.
He told the jury that as he was trying to comfort his new girlfriend in the street when Brett Carpenter had confronted him.
He claimed Mr Carpenter then launched a flurry of punches in his direction.
But the jury rejected his account and found he was jointly responsible for the savage beating.