Farrell was found guilty of exploiting his position, taking advantage of the victims for a long period and committing 62 offenses, including rape and indecent assaults against three girls and nine boys at the time.
Peter Zahra, Sydney district court judge, said Farrell had planned his crimes in advance, including the seduction of his victims and deceiving their parents.
“The offender admitted he had a great deal of influence over the altar boys and he abused that position …This allowed him to offend whenever and wherever he chose,” he said.
“The offender created situations where he was confident he would not be detected even where his sexual abuse was, at times, brazen in the extreme,” he added.
The judge added that Farrell had shown “little evidence of remorse” and had “little insight into the harm he inflicted on the victims.”
Farrell, also known as “Father F”, closed his eyes and showed no emotion during the hearing.
His jail term will expire in 2044 but he will be eligible for parole in June 2033.
In 2013, Australia set up a commission to deal with allegations of serial child abuse inside the Catholic Church in the country.