Tony Reuben Lamprey believed the protected marsupial was killing chickens at his property in the state's rural northwest.
In February 2021 he trapped the quoll and then stabbed it in the head with a reinforcing bar he had sharpened with a grinder.
Lamprey left for work without checking to see if the animal was dead, returning later in the morning to spear it a second time and take photos of it.
He shared an image with a friend on Facebook before disposing of the carcass the next day.
Lamprey in September pleaded guilty to criminal charges of aggravated cruelty to an animal and taking specially protected wildlife without a permit, and was fined $500.
In a Supreme Court judgment published this week, Justice Michael Brett ruled the sentence was "manifestly inadequate".
Justice Brett re-sentenced Lamprey to three months' jail for the aggravated cruelty offence and kept the $500 fine in place for the other charge.
Justice Brett opted to wholly suspend the prison sentence because of Lamprey's lack of relevant prior convictions, the out-of-character nature of the offending and his early guilty plea.
He said Lamprey was extremely unlikely to commit an offence like this again and had provided "significant improvements" to accommodation for his chickens.
In Facebook posts after killing the quoll, Lamprey wrote he had "the last laugh" and "a good quoll is a dead one".
In a police interview he said he believed the quoll had killed 12 of his chickens and he stabbed it because he didn't have another way of killing it.
In a report provided to the sentencing magistrate, a vet determined the quoll was subjected to unreasonable and unjustifiable suffering.
Justice Brett, who said it was unclear when the quoll died, described Lamprey's actions as planned, deliberate and demonstring a high degree of cruelty.
"It is clear that he intended to inflict significant harm or death on the animal in a cruel way by preparing the makeshift spear," he wrote.
Lamprey told the sentencing magistrate he was "really sorry" and he didn't really understand that the species was protected.Â
The spotted-tail quoll is considered vulnerable in Tasmania.
36°C