Crime boss George Marrogi, 36, pleaded guilty to a single assault charge in Melbourne Magistrates Court on Thursday, when he appeared via video link from prison.
He was being escorted to his cell from the prison's video conference rooms on February 25, 2024 when the assault occurred.
Video showed about seven officers, including prison guards and police, were called in to transport Marrogi.
A prosecutor said a senior police officer stepped forward as the door to the "telecourt" room opened.
He took hold of Marrogi, who kicked the officer "in the chest with full force" causing him to be thrown backwards into a wall.
It was not Marrogi's first assault on an officer while in custody and he has also previously set his cell on fire.
He is separately suing Victoria's Department of Justice in a bid to improve his prison conditions, arguing for more freedoms while in custody.
Marrogi's lawyer Daniel Georgiou cited the civil claim in court on Thursday as he said the assault took place at a time when his living condition issues were "particularly pronounced".
"My client has been kept in solitary confinement, has had no access to open air, no meaningful interaction with other humans, and hasn''t been given the opportunity to exercise," he said.
"He is now pursuing his grievances with corrections in a much more appropriate and fruitful manner."
Magistrate Michelle Hodgson said the assault was "quick but brutal" as she decided to increase his prison term by one month.
"It's a significant and forceful kick as you exit a cell door without any provocation," she said.
Ms Hodson handed him a three-month sentence for the assault, but two months of that will be concurrent with his other prison terms.
She warned him that if he continued to commit offences inside prison he will be handed further terms of imprisonment.
Marrogi, who will not be released from prison until 2049, is currently serving terms for murder and drug importation while behind bars.
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