Like most people, Ewan Mitchell is accustomed to anonymity. So during a recent trip to Manhattan, he was surprised by what a hotel doorman asked when he arrived: “You haven’t packed your eye patch?”

Mitchell does not normally wear an eye patch, but Aemond Targaryen, the one-eyed, dragon-riding warrior he plays in “House of the Dragon,” does. The actor is still getting used to strangers making the connection in public.

“I wouldn’t think people would recognize me, but they do,” he said. “I think it’s because of my strong chin.”

This was on an afternoon in May, and Mitchell, 27, was sipping a Coke at the hotel bar. He wore a black Alexander McQueen suit and was preparing to attend the premiere of the second season of “House of the Dragon,” HBO’s “Game of Thrones” prequel that follows two factions vying for the Iron Throne.

When Mitchell made his debut in the latter half of Season 1, Aemond, the willful second son who grows to covet his brother’s throne, quickly became one of the show’s most intriguing and fearsome characters. Paired off with Vhagar, the realm’s largest, meanest dragon, and possessing the most chiseled chin in Westeros, Aemond radiated the quiet ferocity of a predator preparing to pounce.

“When I’m dressed up as Aemond and catch myself in the mirror, he scares even me a little bit,” Mitchell said.

The first season’s shocking ending, in which Aemond’s dragon killed Lucerys Velaryon, Aemond’s rival and relative, signaled to viewers that the one-eyed prince would take on a central role in the looming civil war. In the most recent episode of Season 2, a fiery clash among three dragons established Aemond as the new standard-bearer for his coalition — knows as the Greens — and potentially the realm’s new king.

The upshot is that Mitchell, who had never watched or particularly cared about “Game of Thrones” before joining the prequel, now finds himself as one of the faces of the franchise. To help promote this new season, he has embarked on his first major press tour and has been adjusting to its demands.

When he’s not in character, Mitchell is soft-spoken and occasionally flashes a boyish grin, though he retains much of Aemond’s seriousness and quiet intensity. He is also very private: He stays off social media and in the past has shied away from sharing much with the public. “Once you lose the mystery, you can’t really get it back,” he said.

Still, he knows that Aemond’s key role in Season 2 means he must also embrace the spotlight: “There is a point where you have to go, Now’s the time to pull back the curtain.”

Like Aemond, Mitchell is a second son. He grew up in Derby, an industrial town in the middle of England, and his parents expected him to follow his older brother’s footsteps and work at Rolls-Royce (the aerospace and industrial technology company, not the carmaker).

Inspired by films like “Citizen Kane” and “Taxi Driver,” Mitchell knew early on he wanted to become an actor. When he was 13, his teacher asked each student in his class what they wanted to do when they grew up. One wanted to be an engineer; another hoped to work as an electrician.

“Then it came to me, and I said, ‘I’m going to be an actor,’ and everyone laughed at me,” Mitchell said.

His family could not afford tuition for drama school, so Mitchell attended a two-year vocational school, where he studied design and technology while working part-time at a restaurant and in customer service at a local soccer club. Midway through the program, at 17, he was accepted into the Nottingham Television Workshop, a drama group that trains young people in acting. (Alumni include Bella Ramsey, Felicity Jones and Samantha Morton.)

Through the Workshop, Mitchell landed a leading role in a 2015 short film called “Fire,” about a young man who leaks fire from his hands. Once the short was released, Mitchell downloaded it onto a dozen CDs, took the train to London and stopped by the offices of every agent he could find, handing them each a copy. The one person who called back continues to represent Mitchell.

“By hook or by crook, I wanted to make sure that I was going to be in this business,” Mitchell said.

He was later cast in the ITV period drama “The Halcyon” and in Netflix’s “The Last Kingdom,” and he appeared as one of the Oxford students in the hit film “Saltburn.” But being cast as Aemond in “House of the Dragon” has been his biggest professional turning point by far.

“Since landing him, I feel like I’m able to now steer the course of my career,” he said.

Mitchell had been rewatching the classic Hollywood adventure film “The Vikings” (1958) and musing about how he wanted to play a morally dark character similar to the one played by Kirk Douglas when he received an email inviting him to submit a taped audition for Aemond. When he eventually auditioned in person, he left a lasting impression on Ryan Condal, the showrunner for “House of the Dragon.”

“When Ewan came into the room, he just had this presence to him that I can best describe as unsettling,” Condal said. “It was kind of quietly terrifying the way he performed it, and it was totally different than everybody else. And then he thanked us very politely and left the room.”

Condal recalls asking Kate Rhodes James, the casting director, “Is he always like that?” She replied, “Oh no, he’s just a very intense northern boy.”

To prepare for his role, Mitchell did not watch “Game of Thrones.” Instead, he read portions of “Fire & Blood,” the book by George R.R. Martin that inspired the show, and studied the performances of Michael Fassbender in “Prometheus” and Peter O’Toole in “Lawrence of Arabia,” each playing a figure who wields power for his own ends.

On his first day on set, Mitchell consulted with Condal and decided that he would avoid interacting with Matt Smith, who plays Aemond’s similarly menacing uncle and rival, Daemon, in order to heighten the tension between the two characters. Mitchell had grown up admiring Smith’s performance in “Doctor Who.” But on set Mitchell avoided any eye contact with him, keeping his distance until the climactic scene near the end of the first season when Aemond and Daemon finally face off.

“There’s this addictive kind of quality when you’re in the shoes of a character,” Mitchell said. “When you lose yourself for a moment, it’s almost like a dream.”

When he isn’t acting, Mitchell still lives at his family home in Derby and spends time with his dogs, three whippets named Eva, Bella and Bonnie.

Though taking on a leading role in an international hit and participating in an extensive press tour are new responsibilities for Mitchell, they are challenges he is confident he can master. Learning how to manage and sustain this success is a bit like taming and riding Vhagar, he said.

“Now that I’m on it,” he said, “I’ve just got to stay on the dragon.”