Tasmanian Justice Gregory Geason, who intends to resign, has avoided jail for grabbing, shaking, striking and pushing the woman at a Hobart home on October 31, 2023.
She fell backwards and hit her head on a mantelpiece, suffering concussion and bruising.
Geason also emotionally abused the woman over several months, including by tracking her movements, insulting her and being jealous and aggressive.
The 63-year-old denied the allegations but was found guilty of assault and one count of emotional abuse or intimidation after a court hearing.
Magistrate Susan Wakeling on Thursday described the assault as serious and said the emotional abuse was "not at the lower level".
She sentenced Geason to 100 hours of community service and recorded a conviction as part of a 12-month community corrections order.
"Your moral culpability ... is high. Your love for her does not mitigate your abuse of trust," Ms Wakeling told the Hobart Magistrates Court.
"You have not demonstrated any remorse ... even following the finding of guilt."
Among several conditions, Geason was ordered to continue mental health treatment and not leave Tasmania unless permitted by a probation officer.
Geason, who has been on leave for almost a year since being charged, was smiling as he left the court with supporters but didn't make any comment to media.
The prosecution had pushed for a jail term, whether enforced or suspended.
Ms Wakeling said she took into account the media scrutiny of the case and the damage to Geason's reputation and standing.
"Your 30-year legal career is at an end," she said.
An excerpt of a psychiatrist's report read to the court noted Geason's anxious tendencies and a period of major depression
The report said Geason was highly likely to "deteriorate" with anything other than a "compassionate" sentence.
Gregory Geason intends to resign as a judge, his lawyer told the Hobart Magistrates Court. (Ethan James/AAP PHOTOS)
The woman on Tuesday told the court she spent months in hospital after the assault, was unable to work for eight months and was worried about leaving her home.
Ms Wakeling previously found the woman to be a truthful witness and ruled Geason's version of the assault, in which he said she tripped, to be implausible.
Geason claimed the pair mutually agreed to track each other, denied punching her, said she bruised easily and that he helped her up from the ground after she fell after drinking.
The assault occurred after Geason spotted a selfie on the woman's phone from a male colleague, the court was told.
Geason's lawyer Fabiano Cangelosi on Tuesday said his client intended to resign and considered he no longer had moral authority to continue as a judge.
A spokesman for the state government said it hadn't received any notification from Geason about a resignation. The Supreme Court has been contacted for comment.
Tasmania's parliament has reformed laws to deal with judge misconduct after an attempt to suspend Geason in December was abandoned over constitutional concerns.
Geason is expected to be sentenced in December in a NSW court after pleading guilty to breaching an apprehended violence order.
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