Ashley Sorenson was in the passenger seat of a Mazda ute when 21 eastern grey kangaroos were ploughed down at Tura Beach in September 2019.

Sorenson, 34, on Friday received a maximum sentence of 20 months' prison at Queanbeyan Local Court.

He was one of two men in the car, which was later found by police with a heavily dented front, covered in blood and kangaroo fur.

Sorenson and Nathan Sanger, who was then 18, were at a local club drinking before they went on the callous rampage.

While the driver, Sanger, was found to be mainly culpable, the court heard Sorenson egged him on.

He occasionally grabbed the steering wheel of the ute from Sanger to run into more kangaroos.

"Encouragement came from the accused to start the carnage," magistrate Roger Clisdell told the court.

He described Sorenson's behaviour as disgrace and despicable.

"This was a decision he made cold bloodedly," Mr Clisdell said.

"Once the bloodlust started it was difficult to stop."

Locals awoke to find the aftermath of the killing spree, leaving them traumatised, with police having to euthanise the surviving kangaroos.

The court heard Sorenson moved to the coast to start afresh after a history of violence.

"He was trying to make new friends," his lawyer said.

Co-accused Sanger was found guilty of the majority of the killings last year and given two years' jail, to be served as a community sentence.

Sorenson will be eligible for release in late July next year.

Australian Associated Press