McKenna was linked to big jobs in the Premier League, including Brighton, Chelsea, and Manchester United.
However, he remained faithful to Ipswich and signed a new contract in the off-season.
“I think it always was going to be,” Ashton told Life’s a Pitch TV.
“He’s been instrumental to the rise of this club since the day he joined.
“We work as one. The two of us are the same, we’re just totally obsessed with it and as I’m given the oxygen to do my job by my owners, my job is to put a bubble round Kieran and give him the oxygen and let him do his job unhindered.
“I’m not at the training ground every day, I don’t need to be at the training ground every day, that’s his office. He doesn’t need to be in my office every single day.
“We know what we’re doing, we trust each other and he was the best and the key signing of the summer because once we’d done that, we could all take a deep breath and move forward again.”