An Australian actor who crashed his car and then bit off the ear of a good Samaritan who came to his aid has been jailed for at least two-and-a-half years.

Key points: Bruce Roland Carter crashed his car before attacking a man and biting off his ear

Bruce Roland Carter crashed his car before attacking a man and biting off his ear The judge said the attack was senseless and violent

The judge said the attack was senseless and violent The actor most recently appeared in Picnic at Hanging Rock

Bruce Roland Carter, 36, pleaded guilty in May this year to causing serious harm with intent and aggravated assault.

The District Court heard he had consumed a "cocktail of drugs and alcohol" before he crashed his car at Murray Bridge, east of Adelaide on September 14, 2017.

Carter admitted that when a man who lived nearby came to check if he was injured after the crash, he punched him several times in the face and put him in a head lock before viciously biting his ears.

Carter had spent most of his life as an actor before the Murray Bridge assault, appearing in a number of films and television shows, most recently starring in the Foxtel miniseries Picnic at Hanging Rock as "Tracker Joe".

He also featured in the 2017 Netflix movie Cargo, the 2015 feature film Last Cab to Darwin and was in six episodes of the ABC show Black Comedy.

Judge Simon Stretton sentenced Carter to four years and nine months in jail, describing how the victim had been left physically and mentally scarred by the attack.

"Your senseless, violent offending is extremely serious and has caused great suffering to the victim, who has been left with scarring, disfigurement and damage to his hearing largely for the rest of his life," he said.

"His right ear was partially repaired with stitches, although the stump of his left ear was buried into the skin behind the ear and it was not possible to reattach the amputated part.

"He has lost an entire ear and part of his second ear, he is still suffering the effects of what you did to him."

Victim believed Carter 'would kill him'

The court heard Carter chased down the victim as he tried to get away during the attack.

"[He] believed if he did not get away, you would kill him," Judge Stretton said.

"He managed to get himself off the ground and onto all fours where he was able to push you off and he ran.

"It was a vicious and completely unprovoked attack of an innocent member of the community who was going out of his way to do the right thing by trying to help you."

When police arrived, Carter was aggressive towards them and kicked an officer in the head, which was the subject of the aggravated assault charge.

At the time, he was on bail for an unrelated assault.

Offending 'too serious' to suspend sentence

Judge Stretton said Carter had been extended mercy by the courts on multiple prior occasions through suspended sentence bonds.

"It's of concern that this leniency does not appear to have been sufficient to deter you from drug taking and violence," he said.

Bruce Roland Carter in character in the movie Cargo. ( YouTube )

He said while he accepted that Carter deeply regretted his actions, the offending was too serious to suspend the sentence.

"You have described your remorse in some detail and the horror you feel that you could snap like this and attack someone senselessly when you have always been considered a responsible leader," he said.

"However, this must all be balanced against the permanent disfigurement and trauma that you have caused to a completely innocent member of the public."

Carter told the court he had used alcohol and drugs to "push down" the grief of losing his grandfather who died in January 2017.

His lawyer Mike Norman told a pre-sentencing hearing that his client had been of perfect behaviour while in custody and was focused on rehabilitating while in prison.

He will be eligible for parole in March 2020.