David McBride pleaded guilty to stealing and sharing military secrets on the eve of his trial last year, after legal rulings sunk his defence.
An ex-military lawyer, McBride said he was felt a moral duty to speak up.
A landmark inquiry later found evidence that Australian forces had unlawfully killed 39 Afghans during the war.
McBride is the first person in Australia to be jailed over the war crimes allegations his leak helped expose.
The 60-year-old admits he gave troves of documents to the Australian Broadcasting Corporation (ABC), saying he was concerned about the attitudes of commanders and what he then thought was the “over-investigation” of troops, the court heard.
This guy is a fucking legend. Straight up top bloke. You won’t find someone of better integrity.
He was a military lawyer. He 100% knew he’d go to jail if lucky enough to not be suicided. He still did what was right to find justice for dead people he never knew.