Winmar, 60, had been pushing to get a community corrections order for the May 2025 assault against a woman in Cohuna in northern Victoria.
But Bendigo magistrate Trieu Huynh on Friday found the offending was so serious it warranted a term of imprisonment.
Winmar dropped his head as the magistrate handed down the jail term.
He will also be subject to a community corrections order for one year, with conditions including treatment for alcohol abuse.
Winmar's barrister Dermot Dann KC immediately indicated his client would be appealing both the sentence and convictions.
Instead of being taken into custody, Winmar was allowed to stay in the body of the court while his lawyers filed the appeal paperwork.
He was granted appeal bail shortly before 1pm after prosecutors did not oppose the application.
Winmar ignored questions from reporters as he left Bendigo Magistrates Court, with Mr Dann advising his client would not be commenting.
Winmar maintains he is innocent, claiming the woman was lying about the May 14 attack.
The woman, who cannot be identified, told the court Winmar unexpectedly became angry at her before grabbing and twisting her arm.
He then dragged the woman by the hair, pushed her up against a wall and spat in her face before repeatedly bashing her head into a wooden door.
The magistrate found the attack was "violent and sustained" as he sentenced him on two counts of common law assault and one charge of unlawful assault.
"Your actions were unprovoked and came seemingly out of nowhere," Mr Huynh said on Friday.
Mr Dann had pushed for a community corrections order only, arguing his client had already been punished for the offending.
The former St Kilda star was removed from the Australian Football Hall of Fame and his statue was removed from Perth's Optus Stadium following his conviction.
Mr Huynh accepted there had been some additional punishment for Winmar, although it should only be given limited weight.
Winmar had also taken steps towards rehabilitation for his alcohol abuse issues, having remained abstinent for a year, the magistrate noted.
He had completed programs and seen a psychologist, while also undergoing testing for a possible brain injury acquired during his footy career.
But the magistrate said he had to take into account the impact on the victim, who described feeling worthless and unsafe since the incident.
"The court must impose a sentence to deter others in the community," Mr Huynh said.
Should Winmar's appeal fail, his six-month jail term will kick into effect.
A condition of his bail is to not contact prosecution witnesses.
Winmar kicked 317 goals across 251 games with St Kilda and the Western Bulldogs, and was named in the All-Australian team in 1991 and 1995.
He was the first Indigenous footballer to play 200 VFL/AFL games.
Winmar was well known for his stance against racism in 1993, where he stood in front of an abusive Collingwood crowd at Victoria Park, lifted his jumper and pointed to his skin.
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