Kororia Marsh was jailed for an additional seven months on two counts of entering a property with intent to commit a crime and two counts of receiving stolen property.
Mr Manning said the defendants were at a party on September 24 when four men with links to Black Power went past.
One Black Power associate ran from the partying group after insults had been traded and a group of men ran after him with iron bars, a tyre iron, wheel brace and sticks.
Wiremu Marsh caught up to the man and beat him with an iron bar about his back, head and neck.
Kororia Marsh, yelling out Mongrel Mob insults for Black Power members, kicked the victim in the head and stomach several times as he lay on the ground.
Wiremu Marsh was seen to raise the iron bar high above his head and bring it down on the victim's body, said Mr Manning.
One witness said Kororia Marsh got "a clean shot in the guy's face".
Wiremu Marsh told police he hit the victim only twice on the back while chasing him.
A third person involved in the attack has been dealt with in the Youth Court.
The victim suffered a deep stab wound to his lower back, a 5cm wound above his right eye, a gash to his head, a fractured hand, and welts and bruising to his back.
Judge Philip Connell said the victim might not have been seriously injured but the court had to consider potential injuries, particularly when a person's head was attacked.
Mr Manning said both men had an unenviable record of previous offending including "quite a number" of violent convictions for their age.
Kororia Marsh had received a rehabilitative sentence for similar offending "last time".
Alistair Clarke, counsel for Wiremu Marsh, said there had been no premeditation. The weapon used had been found at the scene.
Cerys Lloyd, counsel for Kororia Marsh, said his involvement began by chance when a fight began with a rival gang.
Marsh came from a background where the use of violence was a normal part of his life.
