A bank account called "Complete Freedom" gave Luke Brett Moore a latitude he never expected.

Over the course of 50 transactions, the Goulburn man exploited a system error to withdraw $2.1 million, spending it on exotic cars, a power boat, paintings, jewellery and a framed Michael Jordan shirt.

Then Mr Moore's freedom was taken away. He was jailed last year, convicted of fraud for having obtained financial benefit by deceiving his bank.

On Thursday morning, the NSW Criminal Court of Appeal found his conviction was a mistake and quashed it, finding no deception had taken place.

"Not guilty," Mr Moore wrote in capitals on Facebook, following it up with a smiley face.

He had been 22 years old in 2010 when he signed up for a new bank account in a Goulburn branch of St George bank.

The first deposit was $441 from Centrelink but the account kept allowing withdrawals even when there was no money and by December Mr Moore owed $9000.

From there he accelerated.

The account headed further and further into negative territory and by August 2012 he owed more than $2 million.

When police raided Mr Moore's home in December 2012, they found signed photographs of Bob Dylan, Usher, Guns N' Roses and Led Zeppelin, as well as the keys to an Aston Martin DB7 Vantage coupe.

He had also bought a 2001 Maserati sedan and a Stessl aluminium 560 Sea Hawk power boat. Police recovered more than $1.1 million sitting in two bank accounts. A jury of 12 convicted him last February of both fraud and dealing with the proceeds of crime.

Mr Moore was obliged at all times to pay the money back.

"To be quite clear about it, the notion sourced in board games of a windfall 'bank error in your favour' is a very poor guide to the position at law," Justice Mark Leeming noted in an appeal judgement supported by Justices Natalie Adams and Desmond Fagan.

Justice Leeming found Mr Moore acted "extremely foolishly" and dishonestly. He had known of the error and continued to borrow knowing he could not pay the money back.

But how had Mr Moore deceived the bank?

The Crown could point to nothing in the man's behaviour that led the bank to continue to lend to him, the court found.

"The unusual aspect of Mr Moore's conduct was that there was nothing covert about it," Justice Leeming found. St George's bank statements chronicled "with complete accuracy Mr Moore's growing indebtedness."

The overturning of the verdict came after he was sentenced to a minimum jail term of two years and three months by Judge Stephen Norrish last April.

"I must confess to some puzzlement at the apparent dismay of the prisoner and people who support him that he was found guilty," Judge Norrish had said, describing the Crown case as "irresistible".

Mr Moore spent five months in jail before he was granted bail last September, pending the appeal of what the Supreme Court described as an "almost unique" case.

Now his freedom is complete.