Now he's hot property, touted this week as the coach of the year by some Australian pundits, and the club is expected to confirm a long-term extension to his deal in the coming weeks.
It's been a significant turnaround and the redemption of Kearney is one of the most remarkable aspects of the 2018 NRL season.
While there have been a myriad of elements behind the Warriors' rise from the ashes this year, and a truckload of individuals involved, it's been masterminded and driven by the 46-year-old from the Kapiti Coast.
Kearney arrived at the Warriors in October 2016 to great expectations, though with a few doubts.
His Kiwis record was unparalleled, his ability to build strong team cultures unquestioned and his apprenticeships under Craig Bellamy and Wayne Bennett impressive.
But his dismal record at Parramatta was a black mark, although the role had been recognised as a poisoned chalice.
Last season started reasonably well, before everything unravelled and they didn't win a game from late June onwards.
That's when the vitriol started, directed at the club heirarchy, the players, but most of all towards Kearney himself.
His constant mantras about "process" and "preparation" were mocked, and all aspects of his ability were under the microscope.
Surely they were extremely tough times?
"All that talk didn't bother me - really," said Kearney. "I knew where we wanted to go. How we were going to get there, how long it was going to take, whether I got there ... I didn't know.
"But they are all lessons and that is the purpose of the not-so-good times. If I let that consume me and just say 'oh shit' and don't try and improve myself, then I am going to stay there. And that's why you have to stay at it ... you have to have the belief."
That mustn't have been easy. Not much went right last year, and such public failure can turn life into a daily chore. Kearney was frustrated with elements of his playing group, but rarely made his feelings public, preferring to concentrate on the rebuild.
"We are going to get this right," he said one day late in the season, leaning on the wall outside the Warriors gym after a training session. "We have to ... that's the only way, no matter how long it takes."
The appointment of Alex Corvo was vital, and the club also nailed the recruitment puzzle, knowing who to hold, who to fold and who to bring in.
But Kearney also had the courage to change his methods, to confront the man in the mirror.
"Whatever I was asking of the players, I had to ask of myself," said Kearney. "How was I going to improve, to get better?"
That started with letting go and taking a narrower focus, even though his head was on the line.
"He's certainly changed this year," assistant coach Andrew McFadden said. "He's been more engaging with his staff and has certainly empowered a lot of people around him.
"From experience, I think that can be really hard to do. Particularly when you are under pressure, there's a temptation to take on more, control things more, but he made a courageous decision to really empower the people around him, in all parts of the staff."
Kearney says it was relatively simple.
"There was some reflection on my behalf and the coaching group voiced their opinions," said Kearney. "I took that on board and said 'yes, there are certainly some good points there'.
"It's a mentality you can get caught in sometimes when you do find yourself under pressure trying to fix everything yourself. The reality is you just can't do that; there's not enough hours in the day."
But Kearney, as ever, is uncomfortable talking about himself and certainly won't countenance any Coach of the Year speculation.
"That stuff is all fleeting," said Kearney. "There are so many parts to it, so many elements at a club, the NRL team is just the tip of the iceberg. It's not even worth talking about ... it's pie in the sky stuff."
