Allwell terrorised Canberra businesses with a string of knifepoint raids over a three-and-a-half month period in 2012.

His heists were deliberately-timed and fast – striking just before closing time, and always getting in and out of the premises within about 100 seconds.

Allwell wore masks or balaclavas and carried a knife in most of the robberies, and usually had a getaway car waiting for him.

But his one-man crime wave came undone when police raided his girlfriend's Gordon home in April 2013 to discover cash trays from six of the robberies.

Allwell went on to commit a further three robberies in May 2013, but police had him in their sights.

Allwell, 28, pleaded guilty in the ACT Supreme Court to 11 counts of aggravated robbery and two of attempted aggravated robbery.

He was sentenced on Friday to 11 years and nine months imprisonment, and won't be eligible for parole until March 2020.

The court heard Allwell's spree – which netted him about $16,922 - started with a knifepoint holdup at a Kambah service station on May 25, 2012.

He then targeted a further 10 businesses – including Conder McDonalds, IGA supermarkets, and several bottle shops – in the following months.

But police stumbled across Allwell shortly after he robbed a liquor store in September.

Officers located his girlfriend's unlocked car in the parking lot of a southside club and discovered a sports bag containing a cash tray, cigarettes, alcohol, and a homemade balaclava about 10 metres away.

The offender fled to Queensland, but was back in police custody in the ACT in February 2013 for a breach of parole on an unrelated matter.

In April, police raided his girlfriend's Gordon home to discover cash trays from six of the robberies.

Police phone taps then caught the woman speaking about the heists.

DNA from the balaclava and fingerprints matched that of Allwell.

CCTV vision captured the majority of the robberies, and Justice Stephen Walmsley said:

"It emphasises, if emphasis was needed, the obvious vulnerability of the staff at all of the stores that had his attention."

In sentencing Allwell, Justice Walmsley noted the offender had been through a "disordered and deprived" childhood.

He never knew his father, and his mother was a drug user.

Allwell developed drug and alcohol problems at a young age, which are still ongoing and were thought to have fuelled the robbery spree.

He doesn't see or speak to his three children or their mother, has no contact with his siblings, and most of his peers are involved in crime, the court heard.

Justice Walmsley found Allwell's judgment was impaired by his use of ice and alcohol before the robberies.

He also recognised the significant impact the crimes had on some victims, including two McDonalds staff.

Allwell was ordered to make reparations to the businesses he robbed.