He was found guilty on four charges of indecent acts and one of sexual penetration.
As he delivered the hugely-anticipated verdict, Chief Judge Peter Kidd said that he chose to "impose a shorter non-parole period" than he would have done otherwise while taking into account Pell's age of 77.
He was convicted of abusing two boys whom he had caught drinking sacramental wine in a rear room of a Melbourne cathedral in late 1996, as hundreds of worshippers were streaming out of Sunday services. A court order had suppressed media reporting the news until last month.
Pell, who has maintained his innocence and plans to appeal, appeared in a Melbourne court after being convicted on five offences including oral rape and molestation of the boys in 1996-1997. It was not immediately clear if he will also appeal the sentence.
"Because [Pell is] so close to the heart of the Vatican power, it is the time now for them to have a more structured approach", Singleton said. He was also not wearing a cardinal's gold ring, which might reflect strict rules on jewelry in the state penal system.
Pell is the most senior Catholic worldwide to be convicted for child sex offences and his sentencing is to be broadcast live on television, reflecting the high level of interest in the case.
Pell will be placed in protective custody and only interact with "vetted inmates" during mealtimes and exercise because his safety is considered "at risk" due to "his profile and the nature of his crimes", reported Lexology.
Pell was Australia's most senior Catholic as the Vatican's treasurer - the third highest ranking member of the Church - between February 2014 and when he was stood down by Pope Francis in August a year ago.
He added Pell could not be made a scapegoat for the church's failings, nor for the trauma inflicted on other victims by other abusive priests.
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Kidd said as archbishop Pell would have "cast a powerful shadow" and thought he could control the situation if caught. Kidd described the assaults as egregious, degrading and humiliating to the victims.
During a pre-sentencing hearing in February, Pell's lawyers submitted 10 character references for the Cardinal - including from former Prime Minister John Howard and Australian National University vice chancellor Greg Craven. He stood silently with his hands behind his back as the judge read his sentence. Pell would be registered as a sex offender for life.
His hearing was broadcast live around the world on March 13 from Victoria's County Court in central Melbourne, the city where Pell formerly served as archbishop and committed the crimes.
Pell's surviving victim - who can not be named - welcomed the sentence but said it was hard "to take comfort in this outcome".
"It is not for me to second guess the verdict", Justice Kidd also emphasised, just after 10am in Melbourne's County Court.
"There is no rest for me. Everything is overshadowed by the forthcoming appeal", the statement said. "I utterly condemn this behaviour", he said.
"I want to give him a hug".
While Gallup said the current scandal is having a bigger impact among Catholics than in 2002, "it is unclear whether Catholics who are questioning their church membership will actually decide to leave the church".