On Friday, he explained his decision further -- casting light on the turnaround from his perceived indecision about whether to stay in Boston.
"I'm happy here," Irving said. "Every single day is at an all-time competitive high. What more can you ask for from an organization than taking a chance as far as getting me out of Cleveland? Really taking a chance regardless of whether I signed back or not.
"They had the same attitude. They just wanted to show me what being a Celtic is about, and that I was going to come around, and I absolutely did. I believe in it. I believe in the franchise."
Irving initially had planned to opt out of the final year of his current five-year deal at the end of the season and was reportedly keen in the past on the allure of the New York Knicks.
Irving told reporters Friday he had been indecisive at the end of last season, coming off knee issues after his first season in Boston.
"I needed just some time to kind of be back in Boston and feel great about different things I wanted to explore in my career," Irving said.
He added he enjoyed "having an environment where I'm challenged on a physical level as well as mental."
The tradition and history of the franchise also appealed to Irving, who revealed he dreams of putting his No. 11 in the rafters one day.
"Obviously, a lot of great players have come before me, but to grow my name in Boston Celtics tradition and history is something I'm glad I can do, and I plan on," Irving said.
Irving caught the front office off guard by telling them he intended to re-sign, as Boston and Irving's camp had not had conversations recently about his contract.
"Me asking the Celtics if they would have me back, that was the first question," Irving said. "I just wanted to make sure. And then at that point, it was an easy decision."
Added Irving: "Honestly, it just was like, 'Man, I do not want to move again.' I do not want to uproot my family and just be dealing with anything new again. No disrespect to other organizations, but here is perfect for me."