In the years that millions of binge-watchers of the hit Netflix series Stranger Things have seen Mr Caleb McLaughlin age from a nerdy 13-year-old to a potential breakout star at 19, one thing remains constant: those eyebrows. Thick and dark and flawlessly arcing, they slip across his face like tossed-off brushstrokes or a set of expressive emojis.

Sitting in his parents’ house in Atlanta, Georgia, his base for the past five years, McLaughlin’s welcoming face is topped on this sunny afternoon by a black Timberland watch cap. He’s using it to mask a bad hair day. His yellow hoodie is emblazoned with the slogan “🐝 Your Biggest Fan”, part of his public campaign to promote self-confidence among teens. (Another trademark maxim, prompted by an acne breakout a few years back: “Embrace Your Face”.) But it’s the brows that beg the question: do they need landscaping now that he’s older?

McLaughlin smiles, patiently, like he might at a dog sniffing around all the wrong places. “Nah,” he says. “They run in the family. My mom used to have thick eyebrows, but she got them waxed. They’ve always been the thing people pointed out, the Caleb signature.”

That signature is evolving. Until now, audiences viewed McLaughlin and his eyebrows mainly through Lucas Sinclair, the smart-stubborn character he plays on Stranger Things. Starring Ms Winona Ryder and a cast who were mostly pubescent unknowns, the sci-fi horror mystery debuted in 2016 to huge ratings and has since become one of the streaming service’s most-watched original series.

That could change. This month marks the release of Concrete Cowboy, a raw father-son drama set in a real-life black cowboy community in Philadelphia, featuring McLaughlin’s first lead movie role, opposite Mr Idris Elba. The feature premiered last September at the Toronto International Film Festival and, with cinemas closed by the virus, was quickly scooped up by Netflix.

McLaughlin shifts in his seat as he talks about the transition to come. He listens intently and laughs, sliding from animated to expansive to thoughtful. At one point, he pulls a tube of lip balm out of his front pocket and coolly applies it before answering another question. His vibe already has transitioned from youthful, kid-actor exuberance to something a lot closer to young-dude charisma.

“This is the role I was looking for,” McLaughlin says of Cole, the troubled 15-year-old from Detroit whose exasperated mother drops him off on Philadelphia’s hard streets to live with Harp (Elba), his estranged dad. “It’s expanding my range as an actor. This is what I do. I got on Stranger Things and got that big break. But I wasn’t acting because I wanted to be famous and a celebrity. It’s what I love to do. I think this film shows my love for it and shows people I’m serious about it.”

McLaughlin started acting at a community theatre in Carmel, New York, because, he says, “My sister wanted me to do it.” It triggered a visceral, kid-simple response: fun. That led him to the Harlem School of the Arts and, at age 11, the role of young Simba in the Broadway production of The Lion King. Nothing seemed out of reach.

“My parents never told me I couldn’t do anything,” he says. “I remember watching superhero movies and saying, ‘I wish I had superpowers.’ And my dad said, ‘You do. You just have to find them.’”

He found something close on Stranger Things. The show became an instant phenomenon. Created by twins Messrs Matt and Ross Duffer and set in a small Midwestern town in the early 1980s, it pulled from a blend of throwback influences – ET, The Goonies, Close Encounters Of The Third Kind, Stand By Me – while adding a stiff shot of Mr Stephen King. Its undertow of Cold War paranoia and parallel universes felt fresh again in the age of QAnon, a conspiracy theory/cult, which, make of this what you will, came into being the same year that Stranger Things debuted.

The young cast became recognised signposts on the wider cultural landscape, often a too-much, too-soon curse. The heat only bonded them. “We were actors, but also celebrities,” says McLaughlin. “It’s different, especially as a child actor, and we went through this celebrity world together. We travelled the world together, shared our deepest secrets. We were all very understanding.”

Between filming seasons three and four of the series, McLaughlin read the script for Concrete Cowboy. He watched director Mr Ricky Staub’s acclaimed short, The Cage, about a black kid growing up in Philadelphia and fell for the director’s gritty poetics. Staub fell for McLaughlin’s audition tape, which he plucked from among 1,500 others.

Concrete Cowboy is an urban Western that centres on the generational subculture of black horse trainers and riders in inner-city Philadelphia. McLaughlin had no experience around horses – “I rode a pony at my sister’s third birthday party” – and spent a month learning how to groom, saddle and ride. When he arrived on set, he knew he had to bring his “A-game”. Besides Elba, the cast included Mr Jharrel Jerome (When They See Us), Ms Lorraine Toussaint (Orange Is The New Black) and rapper-turned-actor Method Man.

McLaughlin was on set for every one of the shoot’s 20 days, usually from early morning until late at night. He loved it. It’s a leading role, but hardly a glam one. His character, Cole, is unrelievedly weathered, unwashed, roughed up. Filmed around horses and stables during a sweltering Philly summer, Mr McLaughlin showered every chance he got, only to have someone on set invariably shout before a take, “Add dirt!”

He smiles. “Cole was down bad.”

The most emotional moments on set happened with Idris Elba. The resentment, longing and love at the heart of their characters’ relationship asked questions of Mr McLaughlin and he admits he was nervous until his co-star put him at ease. “He motivated me to be a better actor,” he says. “He’s a regular dude. Between takes that were super dramatic and emotional, he’d ask me, ‘Do I need to give you anything?’ I’d just say, ‘No, you’re doing fine.’”

Before the film’s most explosive scene, in which Cole confronts Harp for being absent most of his life, McLaughlin says Elba initiated a conversation about their relationships with their fathers “to find the baggage behind the scene”.

“I told him I don’t know what that’s like,” he says. “My father has always been there for me. Then I remembered stories my dad told me. His father wasn’t there for him. Whenever he told me, he cried. I took that emotion and brought it to my work.”

Staub told The Hollywood Reporter he felt like he was “working with a young Denzel [Washington] at the beginning of his career”. Critics have applauded McLaughlin’s performance for balancing “punkish swagger with vulnerability”. Forbes put him on its 30 Under 30 list of entertainers to keep an eye on.

“Honestly,” McLaughlin says, “coming into filming, I forgot I was in Stranger Things. It didn’t matter what I did before. I just threw myself in there.”

Covid shut down production of Stranger Things for six months last year. Staying mostly at home with his family, McLaughlin played a lot of Fortnite and basketball, hit the weights (note his abs on Instagram) and grew facial hair. He also worked on his original music, a brand of R&B he describes as “a smooth, old-school, crispy vibe”, and plans to drop a music video this year.

He was excited to get back on set. Like him, most of the young cast members are now in their late teens. It felt like returning for senior year of high school. They soon could be ageing out of storylines.

When filming resumed in September, health measures kept the close-knit group largely apart off-camera. “The kids’ table has definitely gotten smaller,” says McLaughlin. “But now we can’t even sit together.”

Funny thing about child actors: their characters age along with them, swiftly and in front of our eyes. “He’s grown up a lot and matured more than your average teenager,” McLaughlin says of Lucas, whose romance with girlfriend Max (Ms Sadie Sink) is expected to be tested this season by (spoiler alert) her brother’s death. “He’s more poised, a lot smoother. He’s definitely experienced life a little bit. He’s just trying to figure things out. He’s going through things, but he has his friends going through them with him.”

Fake Lucas sounds a lot like real Caleb. “Yeah, definitely,” he says. “I’ve grown up with Lucas. I remember when I was 13 thinking I can’t wait to be 19. And now...”

Those brows jump, just a little. “It’s interesting to see that unravel itself.” More interesting: watching how it unravels next.