Sharp this year blamed his descent from an elite junior footballer to an ice user with a $200 daily habit on the drug culture he encountered at the Eagles when he joined the AFL club as a teenager in 2004.

The County Court heard in February that while at West Coast Sharp was told by a group of then senior players that he was "either in or you're out", a reference to drug use. He soon became a regular cocaine user and tried ice for the first time.

"Either you used or you left," judge Geoffrey Chettle said on Monday. "You chose the former."

When Sharp returned to Melbourne after three years with West Coast - where he played a handful of pre-season games but no AFL matches - he had addictions to cocaine and methamphetamine.

The court heard on Monday Sharp tried rehabilitation in 2008 but by 2014 had relapsed into heavy drug use and hatched a plan with younger brother Christopher and friend Nathan Lack for an armed robbery.

On December 1, 2014 in Sunbury, the trio used a shotgun and a handgun to rob an unarmed security guard who had $287,000 in takings from several McDonald's outlets, and then fled in a stolen car.

Judge Chettle jailed Sharp, now 30, for nine years and to serve six years before he is eligible for parole after he pleaded guilty to armed robbery, handling stolen goods and trafficking 310 grams of ice from Melbourne to Western Australia.

Christopher Sharp, 26, was jailed for six years after pleading guilty to armed robbery. He must serve at least three years and nine months.

Lack, 35, was jailed for 10 years and must serve at least seven before being eligible for parole. He pleaded guilty to armed robbery and being a prohibited person in possession of a weapon, after police found a military-style assault rifle at his home.

Judge Chettle said the hold-up was an "extremely serious" offence that had a huge impact on the victim, who struggled with anxiety, depression and sleep problems. The victim earlier told the court being robbed outweighed anything he ever experienced during his previous career in the military.

"To look down the barrel of a shotgun and a pistol, unarmed and all alone, is another thing," he said in a victim impact statement.

Ben Sharp's jail term comes less than a month after another former Eagle with long-term drug problems, Ben Cousins, was jailed in Perth for stalking an ex-partner and breaching court orders.

Before Monday's sentence, Judge Chettle acknowledged he had received from Sharp's lawyer a copy of the report into West Coast's drug culture between 2001 and 2007.

The report was prepared by former Victorian Supreme Court judge William Gillard in 2008 but was never released by the AFL.

Judge Chettle said Sharp's drug use did not excuse his crimes, but provided understanding on how a talented sportsman from a supportive family could stray as he did.

The judge said the former footballer was put on a community corrections order in November 2014 for offending which included him being "totally out of control" during an ice-fuelled police pursuit. A court imposed the order just days before the armed robbery.

Judge Chettle said Sharp's rehabilitation was largely dependent on whether he could stay drug free.

The judge was more optimistic about the prospects for Christopher Sharp, who, the court heard, was remorseful and determined to stay drug free for the sake of his partner and their two-year-old son, and had become a mentor to other inmates.

But Judge Chettle said Lack's prospects were doubtful and he was "at the crossroads of life" given he had a criminal history stretching almost 20 years and long-term drug use which had caused a substance-related brain injury.

The three men have each already served more than 500 days in custody.