David William Wonnocott was sentenced to a minimum of one year and four months' jail in Sydney's Downing Centre District Court on Wednesday.
The 51-year-old, who lives with his mother in northern NSW, had an extensive history of sending hateful, homophobic, racist and misogynist messages online, the court was told.
Ms Higgins received a large amount of abuse online after going public with allegations that she was raped by Bruce Lehrmann at Parliament House in 2019.
In 2022, Wonnocott sent Instagram messages to Ms Higgins' partner, David Sharaz, leading the couple to genuinely fear for their safety and ultimately leave Australia for France.
He was also sentenced on Friday over an unrelated online rampage in 2023 in which he sent nearly 50 hateful messages, including to NSW MP Alex Greenwich, who he told to get "full-blown AIDS and die".
Wonnocott pleaded guilty to multiple counts of using a carriage service to threaten to kill, menace, offend or harass.
In a lengthy back and forth with Sharaz over Instagram, Wonnocott threatened to kill him and Ms Higgins and chop their dog into "little pieces".
"She's a useless lying c*** who wasn't raped," he wrote.
"I know the truth c***, I'm going to pay you a visit."
When asked what he would do in paying them a visit, Wonnocott replied with skull and bones and coffin emojis, along with the words: "I'll bury you both."
Mr Sharaz then asked Wonnocott if he knew where they lived.
"I'm going to chop (dog) Kingston up into little pieces, I will follow you home from work and destroy you all", Wonnocott replied.
Before the sentence was delivered, Ms Higgins posted on social media that such acts had real-world impacts for those on the receiving end.
"It's not the first time he has allegedly threatened harm to others - from journalists to members of parliament," she said.
In a victim impact statement read to the court, Mr Sharaz said the threats continued to impact their lives and forever altered their sense of safety.
"My wife and I have been exposed to a lot of public abuse since she came forward about her alleged rape in Parliament House," he wrote.
"However, it was an escalation of death threats by Mr Wonnocott that made us terrified to leave the house alone.
"Over weeks and months, we became petrified that the next person we would encounter would be the nameless, faceless stranger who threatened to end our lives."
In delivering the sentence, Judge John Pickering said the intense public vitriol against Ms Higgins at the time could reasonably lead her and Mr Sharaz to believe the threats might be genuine.
"If we were to process and imprison every moron - and I use that word deliberately - who said something offensive about Brittany Higgins online, I'd be sentencing people for the next 10 years," he said, while giving Wonnocott a maximum jail term of three years and two months.
"But that's really not what happened here. He wanted him to genuinely feel that this was more than just another idiot online."
The amount and range of Wonnocott's apparent hatred "might reflect that he is quite an awful human being who has awful views", Judge Pickering added.
Wonnocott was previously convicted for making offensive comments against gay people, primarily to the ABC, and for making encouraging comments online about the 2019 Christchurch mosque shootings in which over 50 people were killed.
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