Pell, a former top adviser to Pope Francis, is the most senior Catholic worldwide to be convicted for child sex offenses.
County Court of Victoria Chief Judge Peter Kidd said there was a real possibility that at aged 77, Pell could spend the rest of his life in prison.
"In my view, your conduct was permeated by staggering arrogance," said Kidd in handing down the sentence after Pell was convicted of five counts of sexually abusing two children.
"Viewed overall, I consider your moral culpability across both episodes to be high."
Pell has maintained his innocence and has filed an appeal to be heard in June.
The offenses against two 13-year-old boys took place after Sunday mass in late 1996 and early 1997 in a room and a corridor at St Patrick's Cathedral, in Melbourne, where Pell was archbishop.
Pell was found guilty on four charges of indecent acts and one of sexual penetration. He faced a maximum of 10 years in jail for each charge.
"In my view, the first episode in the priest's sacristy involved a brazen and forceful sexual attack on the two victims," Kidd told a packed court.
"The acts were sexually graphic. Both victims were visibly and audibly distressed during this offending," he said, adding Pell's behavior had a "nasty element" to it.
Kidd made it clear the sentence was based solely on the crimes Pell was convicted of by the jury, and that Pell was not to be made a scapegoat for the failings or perceived failings of the Catholic Church.
He set a non-parole period of three years and eight months. He also said Pell would be registered as a sex offender for life.
"I am conscious that the term of imprisonment...carries with it a real, as distinct from theoretical, possibility that you may not live to be released from prison," the judge said.
Pell's sentencing was shown live on television, reflecting the high level of interest in the case, although only the judge was shown and the broadcast was cut immediately after the sentence was delivered.
The senior Catholic was convicted in December, but the verdict was suppressed from being made public in Australia by a court order until Feb. 26, when further child sex offense charges against Pell dating back to the 1970s were dropped.