Altar servers proudly introduced their mothers and choristers remembered seeing him still there after they'd changed out of their robes to go home.

It was those memories that the High Court relied on to overturn five convictions for the sexual abuse of two boys in Melbourne in the 1990s.

After 405 days in prison, he was released on Tuesday.

"There is a significant possibility that an innocent person has been convicted because the evidence did not establish guilt to the requisite standard of proof," said the unanimous decision of Australia's seven leading judges.

Cardinal Pell maintained his innocence from day one and his high-profile barrister Robert Richter QC believed him.

Only a "madman" would do what prosecutors argued the then-Archbishop had, Mr Richter told the jurors who later convicted him.

Cardinal Pell penned a letter from the Melbourne Assessment Prison last August telling supporters "we need not expect the worst" as he awaited a decision from Victoria's Court of Appeal.

He received the worst that time, but not on Tuesday when his final appeal was a winner.

Although the High Court has overturned his convictions, it can't overturn public opinion and Australia's most senior Catholic remains a divisive figure.

Supporters chanted and sang outside court, opponents shouted for him to "rot in hell".

Those same words were spray-painted on St Patrick's Cathedral the night the High Court acquitted him.

Cardinal Pell spent that night in Melbourne and on Wednesday drove with a friend to NSW, where he will stay, at least in the short term, with trainee priests at the Seminary of the Good Shepherd in Homebush.

He had stayed there in the past, including between his Victorian court appearances.

The cardinal smiled and waved at media who followed him up the Hume Highway to Glenrowan in Victoria's northeast.

Prison life was "not too bad", he told them before joking "Before you arrived, it was better here."

Cardinal Pell has so far let a statement, released as he prepared to leave jail, do the talking.

"I have consistently maintained my innocence while suffering from a serious injustice," he wrote.

He was convicted by a unanimous jury in December 2018 of five charges over allegations he sexually abused the two 13-year-old choirboys in 1996, shortly after his appointment as Melbourne's Archbishop.

One of the boys died in 2014, prompting the other to come forward.

The jury relied on his word alone to convict.

But Cardinal Pell says he holds no ill-will toward his accuser.

"I do not want my acquittal to add to the hurt and bitterness so many feel; there is certainly hurt and bitterness enough," he said.

The complainant is now in his 30s, married and a father. In his own statement he said he respects and accepts the High Court's decision.

The standard to which prosecutors have to prove their case - beyond reasonable doubt - is a high one, he said, while reassuring abuse survivors that "most people recognise the truth when they hear it", he said.

"I would hate to think that one outcome of this case is that people are discouraged from reporting to police."

That sentiment has been shared by many public figures.

In the eyes of some in the community Cardinal Pell is still a guilty man - not for the crimes he was acquitted of, but because he is a senior member of a church that for decades hid and protected abusers.

His trial was not a referendum on how Australian church authorities dealt with pedophilia in the church, he reminded people in his statement.

Jurors had been told by Victorian County Court Judge Peter Kidd that the cardinal was not to be made a scapegoat for the failures of the church.

A royal commission examined Cardinal Pell's knowledge of complaints against pedophile priests during his time in Ballarat and Melbourne.

Findings about him and others were blacked out when reports were released in December 2017.

Cardinal Pell was facing charges by then and there were concerns the findings, whether adverse or otherwise, might be prejudicial.

Federal Attorney-General Christian Porter said it is his preference now for findings on Cardinal Pell to be released, but said it could take a few weeks.

For the cardinal himself, what comes next remains to be seen.

It would appear from indirect comments made by Pope Francis hours after the High Court's decision that he still carries favour in the Holy See.

"Let us pray together today for all those persons who suffer due to an unjust sentence because someone had it in for them," the Pope said.

The Vatican welcomed his acquittal, praising him for waiting for the truth.

At one point, Cardinal Pell was No.3 in the Vatican, in charge of the church's finances.

That position was filled after he returned to Australia to fight the charges in July 2017, effectively putting him in retirement.

The cardinal will turn 79 in June, and will lose his position in the papal conclave - the group of cardinals who choose the next Pope - on his 80th birthday.

Australian Associated Press