The chief judge described Pell's abuse of two choirboys in the sacristy at St Patrick's Cathedral as "a brazen and forcible sexual attack on the victims".
Chief Judge Kidd acknowledged George Pell's sentence would have been lower at the time of offending, but says he needs to take into account the current understandings of the issue of child sex abuse.
Pell abused the 13-year-old choir boys in a Melbourne cathedral in 1996, a jury ruled last year.
"I consider the moral culpability of your offences high", CJ Kidd said.
One of the victims died of an accidental heroin overdose in 2014 having never disclosed the abuse he suffered at the hands of Pell.
"There is an added layer of degradation and humiliation that each of your victims must have felt in knowing that their abuse had been witnessed by the other", said Kidd. Pell was found guilty of five counts of sexual assault, in two separate incidents in the late 90s, in December. Each of the five convictions against Pell carried a maximum possible sentence of 10 years each.
The second episode was "brief and spontaneous" but could not be viewed as an "isolated lapse" as Pell had ample time to reflect on his previous abuse of one of the boys, the judge said.
"I do so without hesitation", Kidd said, noting that Pell was a figure of authority.
Finally, Kidd recognised that only one of the victims listed in complaints is alive.
During his trial, Pell's own lawyer described the burly 1.9 meters (6 foot and 3 inches) tall cardinal as the "Darth Vader" of the Catholic Church.
Howard said he was aware of Pell's conviction and pending appeal but that "none of these matters alter my opinion of the Cardinal".
Pell - who appeared in an open black shirt, light tan jacket and cane - nodded to a friend in court after being brought in by police but then stared straight ahead, showing no real sign of emotion during the sentence.
Earlier campaigner against child sexual abuse, Leonie Sheedy, expressed her hope for justice.
"As I directed the jury who convicted you in this trial, you are not to be made a scapegoat for any failings or perceived failings of the Catholic Church".
"The acts were sexually graphic, both victims were visibly and audibly distressed during the offending", he said.
Due to Pell's age, Judge Kidd said he imposed a shorter non-parole period than usual "to increase the prospect of you living out the last part of your life in the community".
He also mandated that Pell register as a sex offender, which the latter did in a courtroom bustling with reporters awaiting the sentencing of the most senior prelate of the Catholic Church to be ever found guilty of child sex crimes.
The judge also warned other victims that "this sentence can not be vindication of wrongdoings against you [other victims]".
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.