"Riotous behaviour can take on a life of its own. It can be unpredictable and difficult to contain," Justice Louise Taylor said.

Growing tensions over COVID-19 restrictions in Canberra's Alexander Maconochie Centre started the November 2020 riot, the destructive results of which are apparent from pictures of the north wing remand unit.

On Thursday, more than three years after the incident, George George was sentenced in the ACT Supreme Court for his involvement.

The 34-year-old serial criminal received a three-year jail sentence after admitting to charges of arson and property damage. He will be eligible for parole in December.

The judge described the riot as an escalation of a planned resistance to a nightly "lock in" and "dissatisfaction for prison conditions" amid pandemic restrictions.

Some of the 27 prisoners in the wing are said to have perceived unequal treatment in the supplementation of cigarettes and were angered at the unavailability of desserts.

Justice Taylor said she was not looking to diminish the difficulties prisoners would have faced with "further restrictions in an already restricted environment" and greater isolation from their families.

While these were "undoubtedly difficult circumstances", she said the riot was "extreme and cannot be tolerated".

George told a pre-sentence report author "he felt he had no option but to join otherwise he would have been labelled a snitch".

However, the offender was reportedly heard referring to himself as being "in charge" during the riot.

Justice Taylor found George was directly involved in at least two fires and he contributed to the maintenance of the other three fires by gathering fuel.

She said the man damaged two CCTV cameras, two tables and a fire hose. She described his involvement as "considerable and deliberate".

A prosecutor previously described him as "clearly a key player".

Mattresses and appliances like computers, a washing machine and a fridge are said to have been thrown onto the fires by others.

The judge accepted at first glance the sentence she imposed, one wholly concurrent with another sentence George is already serving behind bars, may be seen as "unduly lenient".

"The outcome I have crafted is just and appropriate," she said.

Justice Taylor cited a number of her sentencing considerations, including George's traumatic upbringing.

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She described his childhood as being "riddled with disfunction" and said his "background explains to some degree the conduct he engaged in".

"It is important to give full weight to his background for sentence," the judge said.

Justice Taylor also noted George "not unreasonably feels a sense of grievance" about the almost two years it took to charge him for his involvement in the riot.

She said the "egregious" and "indefensible" delay left the man in a "state of suspense".

The judge found George had shown limited remorse for his offending.