Father David Cavanagh has been found guilty of abusing more than 80 boys over a 12-year period, including five who died.
The trial heard how Cavanah, who is currently a priest in Adelaide, abused at least 25 boys and was convicted of five counts of indecent assault.
In total, he was sentenced to more than 25 years in prison.
Cavanach was arrested in 2015.
The court heard that Cavanagas first abuse victims were at St John’s School, St Peters and St Margaret’s College in Adelaide.
Cavagnach also abused boys at the Royal Adelaide Hospital, the University of Adelaide and the Children’s Hospital of South Australia.
The former Archbishop of Adelaide, Robert McLeod, also testified that Cavagans abuse had been “deeply troubling”.
He said there were no good priests in Australia, but there was a lack of protection for vulnerable people.
“There are some priests who are very well respected in Australia,” he said.
“But there are also those who are perceived as less respected.”
He said the Catholic Church was “under pressure” to stop abusing priests, but “not enough is being done to ensure that victims are not mistreated”.
“The system is not designed for abuse to be handled well,” he told the court.
“It has failed the people who have suffered and the church is not capable of dealing with it.”
The court also heard how in 2008, Cavanaghan abused one boy at the time he was teaching at St Mary’s College, St Andrews, in Adelaide’s west.
The case was heard by three psychiatrists and an expert forensic psychiatrist.
The judge also told Cavajas former employers that he should have been banned from teaching in the Catholic diocese for life. “
The victims were very traumatised and there is no justification for this type of abuse.”
The judge also told Cavajas former employers that he should have been banned from teaching in the Catholic diocese for life.
He also told him he should be banned from working in the public sector for life, but the priest was allowed to remain.
He will be sentenced on March 15.