Tasmanian Justice Gregory Geason struck the woman at a Hobart home in October 2023 and pushed her, causing her to fall into a mantelpiece and suffer concussion and bruising,
He was found guilty on October 16 of assault as well as one count of emotional abuse or intimidation for tracking her movements, being jealous, aggressive and calling her names.
During sentencing submissions on Tuesday, Geason's lawyer Fabiano Cangelosi told Hobart Magistrates Court his client would "imminently" resign as a Supreme Court judge.
"(Geason) considers he has lost the moral authority necessary for any judicial officer to sit in judgment over other human beings," Mr Cangelosi said.
"The defendant has reached the conclusion he is not able to sit as a judge."
The court was told Geason, expected to be sentenced on Thursday, had informed the state government and the chief justice of his intention to step down.
The 63-year-old, who became a Supreme Court judge in 2017, had suffered overwhelming shame and public loss of face, Mr Cangelosi said.
"(He) has very limited prospects of future employment. It is not practically open to (him) to return to legal practice in Tasmania," he said.
Fabiano Cangelosi said the judge had suffered overwhelming shame and public loss of face. (Ethan James/AAP PHOTOS)
Geason had lost standing, reputation and was living a lonely existence, Mr Cangelosi said.
"The destruction of his public image and professional life is total," Mr Cangelosi said.
The woman, who read a statement via video link, said she was no longer the same person and spent months in hospital after the assault and couldn't work for eight months.
She said she had become a recluse, set up video cameras around her home and was constantly looking over her shoulder.
"How could someone I loved and respected … do this to me?," she said.
Director of public prosecutions Daryl Coates said Geason's offending was a serious example of common assault and a jail term, suspended or not, should be considered.
Mr Coates said the assault stemmed from jealousy, a desire to control the woman and contained numerous applications of force resulting in extensive bruising and concussion.
Gregory Geason was being treated for his mental health, his lawyer said. (Ethan James/AAP PHOTOS)
The maximum penalties for common assault were 12 months' jail and a $4040 fine, while emotional abuse carried a maximum two-year jail term and $8080 fine, the court was told.
Mr Cangelosi said Geason was being treated for his mental health, posed "practically" no risk of reoffending and the crimes were out of character.
"He loved (her). There remains clear evidence of his support for her during the relationship, in an emotional sense and a material sense," he said.
Magistrate Susan Wakeling previously found the woman, who gave evidence at a week-plus hearing after Geason pleaded not guilty, to be a truthful witness.
Ms Wakeling said Geason's version of the assault, in which he said the woman fell, was "contrived and implausible".
Tasmania's parliament in December abandoned an attempt to suspend Geason, who has been on leave since November 2023, because of constitutional concerns.
His case prompted state law reform to allow for greater action against accused judges.
Geason pleaded guilty in a NSW court on November 8 to breaching a family violence order and is expected to be sentenced on that charge in December.
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