LOS ANGELES — It’s been quite a year for Noen Eubanks.

Last September, he was a high school senior living in the suburbs of Atlanta, acting in high school plays and planning to study video game design one day. Like so many before him, he was also just trying to get through adolescence without being teased.

Then, he started a TikTok account, posted a short video of a joke he wanted to show his older brother, and forgot about it. He came back later to find about 100 views — a lot, he thought at the time. So he kept at it. “I lost my mind,” he said.

Today, he’s got over 5 million subscribers and is living in Hollywood Hills, having been hired as the new face of Kyra TV, a Youtube media company with a Gen Z fan base, earlier this summer. He has a producer, who develops content and brand partnerships for him, a clothing line in the works (it will debut with a sweatshirt) and a salary.

Next, Mr. Eubanks, 18, joked, he might “buy a country.”

“I just kind of went with it,” he said. “Sometimes you just have to let go, because if you hold on to things you’re basically fighting yourself.”

The Zeitgeist, Branded

Like Instagram before it, TikTok has attracted the attention of brands and marketing teams that are eager to stay relevant and appeal to a new, younger audience.

“TikTok is fast paced, it’s funny,” said Brian Salzman, the C.E.O. of RQ Agency, which builds relationships between companies and influencers who do advertisements for them. “For brands, it’s just important to be part of that zeitgeist.”

To that end, more and more companies are hiring teenagers with large TikTok followings as, essentially, brand ambassadors. (Brands are hiring teenagers as consultants, too.) It is important to “not only understand the new and emerging platforms, but understand who is doing it right,” Mr. Salzman said.

There’s the risk, of course, that TikTok may go the way of Vine, or other shuttered social media platforms. But Kyra TV hopes to avoid that fate by investing in talent in ways that make them influential regardless of their platform. The goal, said James Cadwallader, 29, a founder of the company, is to “dominate the world of video, particularly for Gen Z.”

Founded in London in 2017 by four millennial men, Kyra TV produces two Youtube shows, “PAQ” and “Nayva,” in which four hosts complete fashion-related challenges each week. In one episode, the stars of “Nayva” must recreate the Instagram looks of the rapper Rico Nasty for under $100.

Despite being based in London, most of Kyra TV’s audience is in the United States, along with most of the guest stars the company would like to book, so it is opening a satellite office in Los Angeles later this year.

For optimum content creation — and because he moved across the country without family or friends to be in Los Angeles — Mr. Eubanks spends a huge chunk of time with Kyra TV staff.

At a photo shoot at the Airbnb they currently share, Mr. Cadwallader teased Mr. Eubanks about a stray hair growing from his chin. During a drive out to Joshua Tree for a company-directed photo shoot, Mr. Eubanks called Mr. Cadwallader, who is a millennial, a “boomer” who is “just out of it.”

“It’s all relative, mate,” Mr. Cadwallader said. “Just give it five years. Then you’re going to be older as well.”

What’s TV to a Middle Schooler?

The team throws out ideas for Mr. Eubanks — concepts for videos, ways to advance his brand — that he often rejects.

“A lot of things I just know that they’ll work or they won’t work before they even go out,” Mr. Eubanks said. “You can just feel it, you can just tell. Like, you’ll watch it and you just know, is this something that people are going to want to watch or not?”

Over the past year, Mr. Eubanks has learned to post in the early afternoon to catch teenagers and preteenagers as they get home from school. He spends six hours a day on the app (according to Apple’s Screen Time tracking tool) to keep up with the latest trends.

He has a natural understanding of Gen Z humor (ironic and, at times, fatalistic but always playful) that his millennial bosses admit they don’t have.

On the ride out to Joshua Tree, Mr. Eubanks explained a TikTok meme about “the ants.” As with almost every TikTok meme, the concept falls apart with too much explanation, especially because the jokes on TikTok are constantly changing as they are copied, expanded upon and shared.

But “the ants” boils down to something like this: The creator of the video mimics the act of discarding an item, like a piece of fruit, as if it were covered in ants. The next shot is of the same person pretending to be the indignant ant, scowling and waving its antenna.

Teenagers around the country picked it up, iterating quickly and acting out random scenarios, like spraying sunscreen in Dr Pepper (to the chagrin of “the ants”). Mr. Eubanks said this particular meme worked because it reflected constancy in life.

“There are some things that will never change no matter what happens — they will always be the same, and it’s always going to be something that we all have to deal with,” he said. “You could live in Georgia, you could live here. No matter where you’re at, there’s going to be ants.”

Still, constancy is relative term for a digital generation. Almost as soon as the meme took over TikTok, it was gone.

“If I wait three days and make a post about the ants, it could be dead,” Mr. Eubanks said.

How to Make It in America

Mr. Eubanks is the first social media star Kyra TV has signed, and the company is talking to others. Nick Dart, the chief technology officer, developed an algorithm to track the growth of 10 million accounts on Instagram and TikTok before Kyra TV places more bets.

The company’s revenue — projected to be $10 million this year — comes largely from branded content. (Kyra TV also raised $7.3 million in venture capital funding this year, said Devran Karaca, a founder who handles business and operations for the company.)

In 2018 the company won a Digiday Award for best brand partnership for an episode of “PAQ” promoting Converse Fastbreak sneakers. In the 12-minute episode, Converse emails the show’s four hosts to create a “commercial” for the new sneakers. The four young men set about shopping for outfits and scouting locations. The end result is goofy but fun: At one point during the ad (within an ad) one of the hosts drinks champagne out of the sneaker.

While the company’s headquarters will remain in London, it hopes the Los Angeles branch will give it more access to the connections and resources it needs to dominate the 12-to-20-year-old media market.

“All of the biggest creators are here, all of the opportunities are here,” Mr. Cadwallader said. “If I was an alien looking down on planet Earth with no understanding of the complexities of it, I would probably say this is the place you need to be.”

For Mr. Eubanks, the move to Los Angeles is a bit of a fresh start.

Toward the end of last year, he went through what he called his “lowest low that I’ve ever gone to mentally.” His relationship with his parents, divorced and both remarried, was strained; he didn’t like his job; his older brother Damon, his closest family member, had joined the Marines and was leaving for basic training; kids at school mocked him; and he was dealing with anxiety and self-hate.

On TikTok, though, he could explore his personal style and develop his sense of humor.

“For the most part in person, people still weren’t a fan of me, but my fans would reassure me that they do like what I’m doing and so I didn’t care what everyone else was saying and it felt nice,” Mr. Eubanks said. “I was thriving. I was doing what I wanted to, and people were enjoying it. There’s no better feeling than that.”