Crown prosecutor said earlier that day Grace had accosted a couple on the street and was "quite clearly out causing trouble that afternoon".
Edwards became involved when his mate confronted two men who were walking up High St.
One was carrying a box containing new shoes and socks, which Grace mistook for a box of beers.
He and Edwards shouted gang slogans at the victims and demanded they hand over the goods.
Grace grabbed the shoe box after swinging a punch and then chased the men, ordering they hand over their wallets.
The defendants drove off with Edwards behind the wheel but police stopped them about an hour later on Kaikorai Valley Rd.
Edwards blew 578mcg - more than twice the legal limit.
He denied the aggravated robbery charge but was found guilty at trial.
Judge Kevin Phillips accepted Grace, who admitted a charge of aggravated robbery immediately after being charged, was the "ringleader".
"You were there, you were part of it by your actions and the words you were speaking," he told Edwards.
"Your role was much less than your co-defendant but you made demands and you were present and you did nothing to stop the violence that occurred."
The judge said Edwards' previous history of violence called for "the highest condemnation" but he accepted the man was reforming his life.
It was clear the defendant had a previous connection with a gang but that was no surprise when considering his upbringing, Judge Phillips said.
When Edwards was last before the court for a drunken car crash in 2013, he was sentenced to intensive supervision.
The judge said Edwards had used the sentence to change his outlook and overcome the "indoctrination" of a lawless lifestyle.
"I consider it remarkable," he said.
Judge Phillips jailed Edwards for two years and two months and hoped it would not deter him from the positive steps he had taken.
He was also disqualified indefinitely from driving.
Grace is serving a sentence of three years and two months.
