Reigning Supercars champion Kostecki, 26, will switch from Erebus Motorsport to Dick Johnson Racing next season, partnering Will Davison at the Ford outfit.
The recently announced deal ended speculation over his future which had raged since pre-season, when news of a strained relationship with Erebus emerged.
While moving to America to chase a career in NASCAR was initially mooted as a possible option given his history in the US, Kostecki said he was always keen to remain in Supercars.
“No, I haven’t thought about moving away from Supercars,” Kostecki told Speedcafe.
“I still have plenty more I want to tick off my bucket list and would like to win a few more championships, win a Bathurst, more races and all that.
“I haven’t really thought about that next part of my life yet, but I’m solely focused on Supercars.
“I love living in Australia, I’ve got all my friends and family here, I love racing in Supercars, it’s one of the tightest and toughest category in the world. It’s where my bread and butter is.”
Kostecki lived and raced in the US during his teenage years before returning home and embarking on a Super2 program in 2017.
Last year he contested a one-off NASCAR Cup race with Richard Childress Racing and funding from Peter Adderton’s Mobile-X – a ride that Will Brown effectively took over amid the events of 2024.
Asked if he has any plans to race outside of Supercars next season, Kostecki said: “I know for sure I want to get back into my sprint car.
“I absolutely love racing that when I can, so I’d love to jump back in that towards the end of next year if not this year and try and fill up my calendar a fair bit.
“That’s a really big challenge for me. It’s also a different discipline as well. I’d like to broaden myself out and set myself up for some new challenges.
“We’ve seen drivers like that in the past with Shane going off and doing some drifting, some rallying and people like Larson as well that go off and race sprint cars. He’s obviously just done the Indy 500 as well.
“I’d like to do some different things outside of my comfort zone and see how I enjoy it.”