Actor Alexander Sharp’s curious beginning to a promising career

Five years ago, while painting a house in Connecticut, Alexander Sharp decided he’d like to attend the Juilliard School.

Sharp, a British transplant who’d spent two years traveling in Latin America and flipping houses in the U.S. after he graduated from high school, wanted to try acting.

“I like America because it feels — not to sound cliche — but it feels like anything’s possible,” Sharp said. “I wanted to stay here, and I asked this guy what the best drama schools in America were, and he said Yale and Juilliard. I didn’t know how prestigious Juilliard was or much about it. I just saw that it was in the middle of Manhattan and I said, ‘I’m gonna go there.’”

On Sunday, Sharp, now 25 and a Juilliard graduate, will open on Broadway in one of the season’s most challenging roles, as a quirky, 15-year-old boy with an exceptional brain in “The Curious Incident of the Dog in the Night-Time.”

Director Marianne Elliott cast Sharp in the play, an adaptation of the bestselling 2003 novel by Mark Haddon, months before he graduated.

“Yes, I had trepidations about casting a newcomer,” said Elliott, who also co-directed the Tony Award-winning “War Horse.” “He’s never off the stage and drives every scene. However I was seduced by his youth and vulnerability. He has a lovely clarity about him — you can read what he’s thinking and feeling.”

That transparency is useful: “Curious” takes place inside the mind of math whiz Christopher Boone, who falls somewhere on the autism spectrum and who is trying to solve the mystery of his neighbor’s dog’s killing. Written by Simon Stephens, the show won seven Olivier Awards, including best play, in its London run with a different actor in the grueling lead role.

Christopher has few tools to navigate the day-to-day world — he hates touch and doesn’t understand metaphors. The part is physically demanding, requiring Sharp to leap, perform backflips off walls and create a character full of believable tics. His index fingers are blistered from one mannerism he’s adopted, clenching and rubbing his fingers and thumbs.

He also delivers long monologues and spends much of the play assembling a set of train tracks on the stage with a military exactitude.

“For a long time [the train set] was the most stressful thing in my life,” Sharp said near the Ethel Barrymore Theater, where “Curious” is in previews. “I was desperately trying to remember where they go. Also trying to act while being that precise.”

Sharp is slight but muscled from the physical role. Warm and quick to laugh, he suffers from none of Christopher’s obvious social awkwardness, but he shares with the character an outsider’s sensibility.

After his father made money in real estate and retired at 35, Sharp’s family traveled for the first seven years of his life. His mother, a teacher, homeschooled him with lessons that were rigorous but unorthodox. She’d have him read about a castle, then climb it, then write a short story about it. Making the transition to a more traditional school environment was challenging and sometimes bewildering.

“It was hard after growing up like that for a while to sit behind a desk and do things that felt — maybe a little arrogantly — like I’m never gonna use this and it’s pointless,” Sharp said. “The things I didn’t enjoy I couldn’t bring myself to be attentive to.”

He perfumed in regional theater in the south of England but after high school graduation found himself directionless, working at a deli in Devon. “I was so incredibly depressed but had this unbelievable high amount of energy,” he said. “I was very frustrated and kind of trapped.”

At the height of the mortgage crisis, Sharp moved to the U.S. and began flipping houses with a friend, finding two-bedroom homes for $14,000 in cities like Cincinnati and Orlando, Fla. Intermittently he traveled to Latin America, hitchhiking, mountain climbing and looking for adventure. More than once, adventure found him, as when Colombian paramilitary stopped his bus in the middle of the night.

“They slap you about a bit and when you’re on your own you think, ‘Wow, they could do anything they want with me and I couldn’t do anything about it,’” Sharp said.

He auditioned for Juilliard with a scene from Hamlet and, breaking school rules, one from a play of his own, which he lied about and attributed to an obscure English playwright. Juilliard’s rigorous structure was both exactly what Sharp most feared and most needed, he said.

“It’s kind of like my worst nightmare in a lot of ways,” he said. “You’re being told where to be, what to do, how to do it, and harshly critiqued every hour of every day. ... It wasn’t all terrible, just mostly.”

In February of his senior year, a Juilliard graduate who was a reader in the auditions for “Curious” suggested Sharp try out for the role. He found out he got the part on a break from a school play he was directing, an adaptation of “A Clockwork Orange” he’d written.

“I was stunned. I wanted it so bad,” Sharp said. “I had envisaged it, success as an actor, not fame. It’s a very human thing to be drawn to the idea of fame. I don’t believe anyone who says they have zero interest in it. ... But I wanted so badly to be known as a really good actor.”

Life quickly began to change after his casting. He met with multiple agencies — all of them asking him which actors’ careers he’d like to emulate — before ultimately signing with Peter Levine and Joe Machota at CAA.

“I’ve never been very good at answering that question,” Sharp said. “It’s the most common question for an agent to ask, ‘Whose career?’... I kind of just want to do my career.”

For the next year he’ll be Christopher Boone, which is challenge enough, Sharp said.

“This is a very hard character to go really, really deep with and be able to come out of it and live normally as a human being,” Sharp said. “I feel him all the time. It’s very isolating. I think we’re all on the [autism] spectrum, it just depends how far you fall. The fact that for me going to Christopher is just an extremity of myself, an exaggeration of a pre-existing truth, makes it more dangerous to be sucked into it.”

Twitter: @ThatRebecca