The Australian, 22, joined Celtic back in 2010 but made just one appearance for the Bhoys, spending the 2013/14 campaign on loan at Kilmarnock and then last season on loan with Ross County.
Now, Irvine has left Celtic Park permanently, joining Ross County on a two-year deal after impressing on loan there last term.
Speaking to STV, Irvine admitted that it's 'interesting' to have left Celtic after so long at the club, before hinting at a row between himself and the club prior to his move.
"It's an interesting feeling," said Irvine. "It's somewhere I've been for the last nearly six seasons, and they plucked me out of obscurity and have given me the chance to build a platform for my career. Unfortunately, we haven't left on the terms I would have liked to have, but that's all in the past now."
Irvine later clarified the situation, telling The Scottish Sun that Celtic had simply offered him a new contract in order to claim a compensation fee - despite being told that he had no future with Ronny Deila's men - and he could now face Celtic in the season opener on Saturday.
"I’m sure you are all familiar with the compensation laws regarding players under 23, so Celtic did offer me a new contract. But it was essentially just as insurance so that, when I did leave, they were liable to claim compensation money for me," he added.
"There was never any plan for me to stay there. I was told from the beginning of the summer I was free to move on. It was just about the club sorting out the financial side as well as myself. We didn’t part on the kind of terms I would have liked to after nearly six years with Celtic, but I will be hoping to be involved on Saturday."
Should Celtic have given Irvine more of a chance?
Irvine enjoyed a strong season with Ross County last term, but leaves Celtic with just one appearance to his name, giving him little chance to make an impact.
The Australian will now have a real chip on his shoulder given the way he has been treated by Celtic, and there is no better time to make his mark than on Saturday when the two teams meet.
Irvine will look to prove Celtic wrong for letting him leave, but it seems strange for the Bhoys to pluck Irvine out of nowhere and then barely give him an opportunity to prove his quality.