The former Orange resident and Labor politician has been in custody since 2017, when he was jailed for 10 years, with a minimum of seven, after being found guilty of two counts of wilful misconduct in public office.

But on Monday, five Court of Criminal Appeal judges quashed the 69-year-old's conviction and ordered a new trial.

They did the same for former union boss John Maitland, who was jailed for six years, with four years non-parole, on two charges of being an accessory to the alleged misconduct.

Macdonald was alleged to have favoured the interest of Doyles Creek Mining, chaired by Maitland, over the interests of the state when he granted a Hunter Valley coal exploration licence in 2008 without a competitive tender.

However, the appeal judges on Monday found the jury was misdirected at trial on the state-of-mind element of the offence.

Jurors should have been directed that Macdonald could only be found guilty if he wouldn't have exercised his powers to grant consent to apply for the licence, and grant the licence itself, except for the illegitimate purpose to benefit Maitland and DCM, the appeal court held.

His lawyer, Phillip Boulton SC, wasted no time applying for bail in the NSW Supreme Court and it was granted by Justice Natalie Adams, prompting Macdonald's wife to cry and embrace a supporter.

Outside court, Anita Gylseth told reporters she was "overwhelmed" and looked forward to seeing her husband.

Under his bail, Macdonald will have to reside in the Blue Mountains, report to police weekly, not approach any international departure points or contact prosecution witnesses except through his lawyer.

Maitland, now 72, who was also granted bail, will reside in Sydney's eastern suburbs but otherwise faces similar conditions.

After the appeal judgement, Premier Gladys Berejiklian told reporters she hadn't kept up with the news "but I'll look at that to see if there's any further action the state will take".

Their matters will next be in court on Friday.