A panel of judges upheld findings that Ms Berejiklian engaged in "serious corrupt conduct" by breaching public trust through her clandestine relationship with disgraced party colleague Daryl Maguire.
Gladys Berejiklian said she always worked her hardest to look after the people of NSW. (Dean Lewins/AAP PHOTOS)
"There was evidence that Mr Maguire pressed the applicant to exercise her public functions in particular ways to support his causes and that the applicant responded accordingly," the judges said.
The panel found Maguire had "direct, immediate and informal" means of communicating with Ms Berejiklian and did so without any suggestion of a boundary between their personal lives and her public duties.
In a statement following the ruling, a defiant Ms Berejiklian pointed to the "limited" way in which ICAC's findings could legally be challenged, noting the court could not perform a merit-based review of the corruption findings.
"Serving the people of NSW was an honour and privilege which I never took for granted," she said.
"I always worked my hardest to look after the welfare and interests of the people of NSW."
An overturning of the corruption finding could have damaged ICAC's standing after the integrity agency was criticised for the time taken to deliver its report and its failure to recommend criminal charges.
But Ms Berejiklian's case was dismissed by two of the three Court of Appeal judges, with one dissenting on the question of whether Ruth McColl, who was appointed assistant commissioner to help with the inquiry, had authority to prepare the ICAC report.
Daryl Maguire told Gladys Berejiklian in 2018, "I am the boss, even when you're the premier." (Bianca De Marchi/AAP PHOTOS)
While that appointment to the commission expired in October 2022, she was kept on as a consultant for a further eight months before the long-awaited report was published.
Court of Appeal president Julie Ward said she would have quashed ICAC's findings based on Ms McColl's role being more than an advisory one and the commission therefore acting beyond its power.
But she agreed that Ms Berejiklian was aware of her obligation to disclose conflicts of interest and chose not to do so.
That finding relied on recorded conversations that formed part of ICAC's investigation, including a 2018 phone call in which Maguire said, "I am the boss, even when you're the premier."
Ms Berejiklian replied: "I know."
The judges found the exchanges supported a view that Maguire pressed Ms Berejiklian to support his causes and that she was prepared to respond by doing so.
ICAC deemed Ms Berejiklian''s corrupt conduct included her sitting on a cabinet committee tasked with considering millions of dollars worth of funding arrangements pushed by Maguire for his Wagga Wagga electorate.
Gladys Berejiklian sat on a cabinet committee considering funding for Daryl Maguire's electorate. (AAP PHOTOS)
Between 2016 and 2018, as treasurer and then premier, Ms Berejiklian was involved in approving or supporting allocations of $5.5 million for the Wagga-based Australian Clay Target Association and $10 million for the Riverina Conservatorium of Music.
Ms Berejiklian's lawyers argued the corruption findings were "illogical" as the watchdog had also deemed there was insufficient evidence to pursue criminal charges.
But the appeal judges rejected that argument, noting that different rules of evidence and standards of proof applied before ICAC and criminal courts, and there was nothing irrational about the corruption finding.
Ms Berejiklian stood down as premier in 2021 at the start of ICAC's investigation, later walking away from her long career in politics to pursue an executive role with telecommunications giant Optus.
An Optus spokesperson acknowledged the outcome of the judgment but declined to publicly comment further.
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