The 2021 Le Mans 24 Hours winner and team principal of Toyota's WEC arm was announced on Wednesday at La Sarthe for a one-off NASCAR outing at the Indianapolis road course in August, driving a third 23XI Racing Camry.
Kobayashi will take over the #67 car previously driven by Travis Pastrana to an 11th place finish at the Daytona 500 for his first outing in a stock car, following in the footsteps of fellow ex-Formula 1 racers Kimi Raikkonen, Daniil Kvyat and Jenson Button who have all made Cup debuts in the last 12 months.
Joining Toyota Racing Development USA president David Wilson on stage, Kobayashi revealed that he "was for a long time" searching for the right opportunity to go stock car racing as "actually my memory, [the] first racing on TV was actually NASCAR".
"When I was like four or five years old. I said, 'wow, that's cool!'" he said.
"And the first time when I raced a go-kart, honestly I didn't know Formula 1.
"What I saw when I was really young was a NASCAR race, because it was an oval. And I remember thinking one day to race in NASCAR was my dream."
Even after his F1 career, which yielded a single podium from 75 race starts between 2009 and 2014, Kobayashi found that his NASCAR dream remained in the back of his mind.
He repeatedly asked Wilson for an opportunity, which yielded a simulator try-out on the virtual Bristol oval.
"I always keep saying, 'I want to try' and finally [we] made it happen," he added.
Wilson explained that they had "been working on this assignment for a couple of years".
"Kamui has become a friend and we're doing some really neat collaborations elsewhere," he said.
"We understood that it was his dream one day to race in NASCAR, and so with this great new Next-Gen Camry TRD, the stars and planets started to align themselves."
Six road courses feature on the Cup Series schedule in 2023, and Kobayashi's choice of Indianapolis came down to scheduling around commitments in the WEC and Super Formula with KCMG.
"I have a still racing in WEC and also I'm doing the Super Formula as well in Japan so obviously to find no clashing schedules as a part of a race in NASCAR is quite tricky," he explained.
"Also, we need to have a lead-in time to have a simulator session, seat-fitting, couple of test days probably, that makes not fit at all for any other track. And the only one we find is the IndyCar track.
"Definitely I want to do more but unfortunately, it was my schedule this year [and] this is the only one we found."
Kobayashi will be the first Japanese driver to start a top-level NASCAR race since Hideo Fukuyama at Sonoma Raceway in June 2003, although Akinori Ogata has made a handful of starts in the Xfinity and Truck Series in recent years.
When asked by Autosport if his NASCAR debut was likely to lead to an uptake in interest and potentially new drivers making the switch from Japan, which held three exhibition races in Japan during the late 1990s, Kobayashi said: "Honestly I think yes.
"Japanese people being in motorsports or [other] sports in United States is something [like a] big dream. We always say it.
"When you look at the baseballer, Shohei Ohtani, he's a very famous in Japan but he's been famous in the United States as well. We always call [it the] American Dream, and I think that's what we need to make (the) door open.
"This is [why] I really want to try, because NASCAR is one of the biggest sports in the United States and if I have the opportunity, this is the way I want to try.
"I'm really proud to be here to announce it, not full-season but even this one race, I think this opportunity is important for me."
His 23XI Racing team has already won a road course race this year, with Tyler Reddick taking the checkered flag at the Circuit of the Americas.
