Manny Waks was aged between 10 and 12 when Zev "Velvel" Serebryanski assaulted him at the Yeshiva Centre in Melbourne's southeast sometime between 1986 and 1988.
Serebryanski, who was in his early 20s at the time, had developed a sexual interest in the then-child and cornered him upstairs one night during the religious Shavuot festival.
The man sat down on a bench next to the pre-teen and groped at his groin before pulling him into a bathroom and sexually assaulting him.
In sentencing the now-62-year-old to a suspended jail term, Victorian County Court Judge John Kelly described Serebryanski's actions as transgressive and predatory.
"It is an attack on innocence, an attack on childhood," he said on Friday.
"You said you were only following your victim's lead ... that is a transparently absurd proposition."
Mr Waks reported the abuse to police in 1996 and confronted Serebryanski about the allegations at his home in Brooklyn, New York, in February 2017.
In a recorded conversation, Serebryanski told Mr Waks he never wanted to harm him, he loved him and he had only wanted to do what the boy wanted.
Judge Kelly described the comments as damning and self-serving, saying any remorse was "eroded by pedophilic justifications".
The judge accepted Serebryanski had served 99 days in a New York jail cell before he was extradited to face court in Melbourne in 2023.
His rehabilitation was also largely complete due to the years that have passed without further convictions, Judge Kelly said.
"I do not believe you will reoffend," he said.
Judge Kelly told the court he needed to consider sentencing practices of the 1980s and noted prosecutors did not oppose a partially suspended sentence.
He ultimately jailed Serebryanski for three months but reckoned the period as already served, with the rest of his prison sentence wholly suspended for three years.
Mr Waks, an advocate for victims of child sexual abuse in Jewish communities, told AAP he was unsurprised by the sentence but relieved the case was closed.
"As of today, my battle is over," he told AAP.
"It doesn't mean I will stop advocating. I will always stand up on these important issues."
Both of his abusers - Serebryanski and convicted rapist David Cyprys - had now been held to account, Mr Waks added.
"For me, this has never been about revenge," he said
"It's about justice, accountability and prevention. From my perspective, I achieved those things."
Serebryanski ignored questions from reporters as he walked from the County Court on Friday.
He will only return to prison if he commits another offence within three years.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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