At the top of this year’s list of highest-earning YouTubers is Ryan, a little boy who stands just over 4 feet tall.

He’s 7 years old. He just lost his first tooth last month. And, according to Forbes, his YouTube earnings reached a cool $22 million in 2018, thanks to the billions of views his Ryan ToysReview videos have garnered.

The videos — which feature Ryan playing with and unboxing toys and mystery eggs in his home — have earned Ryan 17 million YouTube channel subscribers and have been collectively viewed more than 25 billion times.

The secret of Ryan’s success? Retail experts say it’s all about authenticity.

“Ryan is an amazing little boy and kids are just enamored with him,” said Jackie Breyer, editorial director of The Toy Insider. “They can relate to him. And kids just love to watch. They want to play with him, they consider him a friend of theirs. And he has all the coolest toys.”

NBC News recently spent a day with Ryan and his parents, who don’t make their last name public out of a desire to protect the family’s privacy.

The reality of how "big" Ryan has become in just a few years hasn’t fully hit the family, explained his parents, Shion and Loann, as they stopped with their pint-sized star to greet young fans during a recent visit to a Los Angeles-area Walmart.

Ryan and his parents posted their first videos to YouTube when Ryan was 3 years old.

Ryan’s mom said she’d tried her hand at posting YouTube videos when she was in college. When she had Ryan, she said, she thought she’d try YouTube again, this time with her toddler son taking center stage. The results were overwhelming.

“Originally, we just uploaded videos for our families, outside the U.S., just to share,” Ryan’s dad, Shion, told NBC News. “All of a sudden, we noticed many other people watching it, too.”

Ryan’s primary audience is comprised of 3- to 6-year old children and their parents.

Earlier this year, Ryan went beyond the world of videos — putting his name and face on a collection of Ryan’s World toys that’s now being sold at Walmart, Target and on Amazon. The collection features products that Ryan loves to play with his and has shown his fans in his videos — including slime, putty, and Squishies.

Arguably the hottest products are his golden mystery eggs, which are typically sold out in stores and are commanding big bucks on eBay — up to several hundred dollars each.

According to Chris Williams, chief executive officer of Pocketwatch, which represents Ryan and helped broker his toy deal, the magic of Ryan lies in kids’ abilities to relate to him.

“They see themselves in Ryan in a way that I don't think they do with maybe fictional characters, or with stars who come from TV and film,” said Williams. “He’s just a regular kid.”

Williams believes Ryan is something of a pioneer — one of the first YouTube stars to tap into a young public’s desire to purchase and play with items backed by their favorite YouTube personalities.

“The audience of kids and families had really moved to YouTube from linear television. But the business of that, and the other things around that ecosystem, like retailers, and book publishers, and game developers, hadn't moved as well," said Williams.

But Ryan, Williams said, has helped change all of that — and now that his move into the retail arena has proved successful, he’s opened the door for more YouTube stars to similarly market their own products.

“I think by this time next year, for holiday 2019, we will see more product based on, not only Ryan, but also other Youtube stars,” said Breyer. “There are some other kids out there who have millions of subscribers and millions of views on their videos who [have] products in the works for 2019.”

Also growing and evolving: Ryan’s empire. He’s the subject of a new early reader book from Simon & Schuster that was released earlier this month, and he’s behind a new mobile game and collection of toys, to be released in 2019.

And soon Ryan may no longer be the only YouTube star in the family. There’s talk Ryan’s younger twin sisters, 2-year-old Emma and Kate, may soon try their hand at videos. Ryan’s parents say there are no firm plans yet — but note the girls are “very interested” in what Ryan is doing and that they are open to the idea.

For now, Shion and Loann say they are intent on keeping Ryan’s feet firmly planted on the ground and on helping Ryan continue to enjoy being a little boy.

Making videos, his parents said, is just one of many activities that interest him.

“Every week he does swimming, he goes to a piano lesson, he does tennis, he does soccer,” said Loann. “The other day he said he wanted to do gymnastics.”

Ryan attends public school and is surrounded by a community and teachers who know he may be a big deal on YouTube, but are helping him to keep things real in his day-to-day life, said Loann.

And, his parents say, even if their 7-year-old is a multimillionaire, he’s still a normal first grader with normal kid issues.

“I think eating is probably the biggest problem we have,” Shion told NBC News. “Ryan's a very picky eater. Only certain things he eats."

Ryan’s parents say he’ll continue to make videos — as long as it remains a source of fun.

“We sit down with Ryan, and we're like, ‘Okay, what do you want? What kind of videos do you want to film today?’” shared Loann. "'Do you want to film a skit, or do you want to play with games?’ And he's the one who is usually leading us to what type of videos he wants to make.”

“You can tell if kids don't want to be in the video,” said Shion. “You can tell by watching them. So it's very important that the kids actually want to be in the video.”

As for Ryan’s hopes for the future, he told NBC News he wants to be a game developer.