The team will run under the Irwin Racing banner after welcoming the tool manufacturer back to the sport having last appeared at Erebus Motorsport in 2013.
“I'm really excited, it was a big call to go to Team 18 but now I've met the team and sponsors and seen what's coming it's really exciting,” said Winterbottom, who replaces Lee Holdsworth at the team.
“I think it's going to be a good year and when it all comes out about the staff and sponsor everyone will understand why I've made the move and it'll make more sense.
“I haven't thought about the badge to be honest.
“I've looked at the opportunity not the brand of car and haven't quite come to terms with that at the moment but from the inside they all look the same and I think the opportunity that Charlie and Team 18 offered was too good to turn down.
“The Holden will be different but at the same time if we are winning races I'll be happy to do it in whatever equipment we have.”
Winterbottom says the opportunity to join a smaller operation is a refreshing one despite the added challenges of being a single car outfit.
“A small team is refreshing; to have the whole team working together for one goal and all working together,” he added.
“Every person has to deliver to get the result and that's myself, the engineers, everyone.
“I'm sure there will be some difficulties like pit stops and data sharing but in saying that with the weaknesses comes the strengths and having 10 to 12 crew with one goal and having a little family going racing is going to be a great approach.”
Team owner Schwerkolt hailed the driver announcement as a momentous occasion for his outfit.
Speedcafe.com understands that the squad's Triple Eight built Commodore will be upgraded to the latest equipment for next year and will also welcome new personnel.
“To have Mark drive with us in 2019 is really big, he brings a whole range of experience and accolades to Team 18,” said Schwerkolt.
“We've got some new engineering and partnerships forming which will take us to a new level in 2019.
“We have more to announce in coming weeks but I can't wait to reveal the car next year.”