A jury unanimously found Pell guilty on one count of sexual abuse and four counts of indecent assault against two boys at St Patrick's Cathedral in Melbourne in late 1996.
Pell, now aged 77, was accused of cornering the boys - then aged 12 and 13 - in a small room at the back of the cathedral after he caught them drinking the sacramental wine following Sunday mass. He then forced them to perform a sex act on him.
The jury also found Pell guilty of indecently assaulting one of the boys in a corridor more than a month later.
The cleric, who remained free on bail throughout the proceedings, denied all the charges and an initial trial ended with a hung jury in September. He was convicted on retrial on December 11.
A wide-ranging suppression order from the judge had prevented the media from reporting even the existence of court proceedings and the ensuing trials since May.
But the order was lifted on Tuesday when prosecutors withdrew plans for a second trial on allegations from the 1970s.
The cardinal was archbishop of Sydney and archbishop of Melbourne before he moved to the Vatican where he became the top financial adviser to Pope Francis in 2014.
Pell, who has been free on bail, faces as many as 50 years in prison for the offences with sentencing due to begin on Wednesday when he is expected to be remanded in custody.
"Cardinal George Pell has always maintained his innocence and continues to do so," said a statement issued by his lawyers, who added that they had lodged an appeal against the conviction.
The statement said that numerous allegations and other charges against Pell had already been withdrawn or discharged.
The announcement of Pell's conviction comes in the same month that the Vatican announced Francis had approved the expulsion from the priesthood of a former high-ranking cardinal in the United States, and days after he concluded the first-ever summit of Catholic leaders on preventing clergy sexual abuse and protecting children.