The former Vatican number three, who managed church finances and helped elect two popes, was sentenced in a Melbourne court on five counts, including oral rape and molestation of boys in 1996-1997.
Judge Peter Kidd, whose remarks were broadcast live on television, said the 77-year-old was guilty of "appalling" and "breathtakingly arrogant" attacks that took advantage of his position of authority over the boys, then aged 13.
Kidd said the cardinal, with his "significant history of cardiac problems", would be eligible for parole in late 2022, but acknowledged he "may not live to be released from prison".
In pronouncing the sentence, well short of the maximum 50 years, Kidd cited Pell's "otherwise blameless life". The judge said Pell had "effectively reformed" and was not a risk to the community.
Pell signed the sex offenders' register before leaving the court in handcuffs for an undetermined facility.
Appeal hearing in June
The cardinal maintains his innocence and will appeal.
The prospect of further legal proceedings and the relatively short sentence tempered victims'
The victim named only as "J" said in a statement, read by his lawyer, that everything was "overshadowed by the forthcoming appeal."
The father of the other victim, who died of a drug overdose in 2014, said through his lawyer that the length of Pell's sentence was "disappointing".
Pell did not take the stand in his defence, but in a video of his police interview in Rome in 2016 he called the allegations against him "deranged falsehood" and "a load of absolute and disgraceful rubbish".
Pell's appeal has been slated for a hearing on June 5 and 6.