• Ever wondered what it’d be like to win millions in a MrBeast competition? Jeff Allen did exactly that. He reveals exclusively to Fortune what it’s like winning $10 million—the largest prize fund ever awarded for a competitive reality TV show—how he’s investing the cash, and why he’s not going to let it put a pin in his career.

When MrBeast—whose real name is Jimmy Donaldson—put out a calling last year for 1,000 contestants for a new reality competition show, Jeff Allen was skeptical. Allen had just lost his job, and he was dealing with the realities of having a son with a rare brain disease. But, he decided to take a leap of faith and made it on the show as contestant number 831.

After weeks of filming that took him to Las Vegas, Panama, and Toronto, he was crowned victory and left $10 million richer, the largest sum ever awarded in a competitive reality TV show—but the adjustment hasn’t been as easy as he expected.

“It’s a blessing to win $10 million and have 10 million eyes from all over the world on you and hear about my son’s rare brain disease,” Allen tells Fortune. “But also it’s a little daunting.”

While during Beast Games, Allen had to deal with pulling a monster truck, finding a golden ticket, and opening mystery briefcases, he’s now fighting new challenges—like figuring out what to do with his newfound millionaire status and how to stretch it as far as possible to find a cure for his son’s disease.

In it for the platform—not the money

Allen’s youngest son, Lucas, was born with a rare genetic disorder called creatine transporter deficiency (CTD), which has caused a deficit in his brain development. According to the Association for Creatine Deficiencies (ACD), an estimated 35,000 individuals have the condition. Allen has made it his life’s mission to bring awareness to CTD—and one day help find a cure for it.

That’s why during the countless times Allen had the opportunity to take one of the game’s bribes—even $1 million—to leave the game, he stayed. During each episode of Beast Games, a portion of the original 1,000 contestants were eliminated or left with a bribe, with only six remaining by the 10th and final part.

However, Allen says he was never in it for the money. By episode eight, Allen was spotlighted, and he shared Lucas’s story with the world. By episode 10, it was hard to not root for Allen, knowing what he hoped to do with the money.

“My ultimate aim for joining Beast Games was to have a platform to talk about my son—Lucas’s rare brain disease,” he tells Fortune, adding that it wasn’t until episode 10 that he realized he could even take home the life-changing amount of cash.

“I realized, wait, I’m this far, I can also win this thing,” he says. “I got the best of both worlds, and it’s crazy to even think back to it.”

In total, Beast Games won 44 Guinness World Records while recording, including the largest physical cash prize on set.

After recording for the show wrapped up in the fall, Allen and his family had to stay quiet about his victory, but it didn’t stop him from raising awareness for CTD. He recently spent 18 days rucking across California. He hiked 365 miles in total, with weights on his back, and raised over $140,000 for the ACD. As a volunteer board member of the organization, he hopes the whole world will soon know about the disease.

“Our aim as parent advocates is to find solutions for our kiddos and to help families who aren’t even who aren’t even formed yet, to be able to avoid struggling and suffering the way our families do today,” he says.

Heidi Wallis, executive director of the ACD, says Allen has “jolted” the organization’s parent-powered movement. During the week of the Beast Games finale, the ACD website experienced 100 times the usual traffic. Weeks later, website visits are still 10 times higher than usual.

“Together, we are creating a future where every child with CTD can be diagnosed promptly and treated effectively. Thanks to this elevated awareness, more families have found support — and hope for a cure,” Wallis says.

Allen hopes to raise $40 to $50 million for the organization to hopefully fund a clinical trial and find a cure.

So, what do you do with a cool $10 million?

At the start of Beast Games, the grand prize was only set to be $5 million, but a plot twist in the final episode caused the pot to double to $10 million. Allen says that only after the show was released was he wired the money.

Immediately, Allen moved a majority of his money into a high-yield U.S. treasuries cash reserve, and his financial advisor at Arta Finance, Emmy Sakulrompochai, helped him set up an estate plan that included a special needs trust to ensure his son has long-term financial support.

Allen also donated $200,000 to charity to help fund research for CTD, with plans to make a larger donation later this year.

“His goals are pretty clear, that he wants to stand up all his money,” Sakulrompochai tells Fortune. “He wants to be able to grow and invest that over time so that he could create impact as much as possible within the research.”

She adds that for anyone who encounters a new large sum of money, it’s critical to think about long-term goals before spending it. Otherwise, you might run into major tax issues later or simply end up losing it all like some lottery winners. Allen may owe the government $2.5 million due to income taxes, but by investing the money in the meantime, he may be able to lessen the burden.

And despite the challenges that come with being a millionaire and internet sensation, Allen says he isn’t going to let it all put a permanent damper on his career.

“I do have an appetite for business,” Allen says. “I love the sales and operations side of it. Right now, I haven’t dove back into anything quickly, but it’ll be hard to keep me away for a long time.”

“At the end of the day, it’s good problems to have,” he adds. “Overall, I’m happy and I’m blessed.