The two teen girls reported their then-PE teacher's abuse to the school in 1984 and an education department investigation occurred instead of a police probe.
The man, who has not been named to protect the identity of his victims, moved schools to a nearby town.
He did not face trial over this offending until 2025.
The teacher then moved to NSW in the 1990s, where he had four children, one of whom he subjected to 14 years of "depraved and sadistic" abuse, a judge found in 2016.
From age five to 19 the girl experienced sustained sexual abuse and torture, often while she was detained in a dilapidated tin shed which used to be a chicken coop.
The man, now aged 69, is serving one of the longest Australian sentences for child abuse over that offending - 46 years - and will be eligible for parole when he is 96.
He faced Victoria's County Court on Friday over the offending against his former students.
A jury found him guilty of five offences in December, including sexual penetration of a child aged under 16, for offending while teaching at Traralgon High School in Victoria's Gippsland region.
One of his victims read an emotional statement to the court on Friday, labelling the man a "disgusting pedophile".
He was convicted of four counts of indecent assault against the girl, who was in year 11 at the time and would help him teach gym class.
In 1983, he touched her inappropriately, including by using a skinfold test to measure private parts of her body.
"I lost years of emotional and sexual development, and this changed my life negatively for decades," she told the court.
The former student recounted her experience being interviewed by the education department as being "confused, defeated, humiliated" with "men in black suits questioning why, how?"
"She didn't know, only that she didn't want others to endure," the woman said.
Another student, who also reported her abuse to the school, was 15 when he sexually penetrated her while she was under his care, supervision or authority as her teacher.
The man continued working at various schools after leaving Traralgon in 1983, moving to Presentation College in nearby Moe and then St Anne's Gippsland in 1989.
Prosecutor Sandra MacDougall asked the judge to take into account his subsequent offending against his child in sentencing as he "did nothing to rehabilitate himself".
She said he must be treated as a serious sex offender and the sentence should include time to be served on top of his NSW term.
The man's barrister Paul Kounnas argued there should be concurrency in the Victorian sentence, meaning it is served simultaneously to the NSW term, due to delays and as he "will be very old if and when he is released from prison".
Mr Kounnas submitted two character references for him from two of his children, who remain supportive.
He will be sentenced on June 16.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
Kids Helpline 1800 55 1800 (for people aged 5 to 25)
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