As Lex on Discovery Kids' sophomore hit "Flight 29 Down," Allen Alvarado plays a hyper-intelligent, preternaturally poised kid who, despite his small stature, always seems above the fray and ahead of the curve.

But in real life, the 10-year-old Alvarado is ... pretty much the same, actually.

"He's just an amazing young man," says Rann Watumull, co-founder of Hawai'i Film Partners, which co-produces the show with creators Stan Rogow and DJ MacHale. "He's smart, energetic, willing to work and he has a great attitude. Everybody is just enthralled with this kid."

The youngest member of the ensemble cast, Alvarado has already distinguished himself with his precocious professionalism and his ability to mix comfortably with producers, directors, crew and fellow actors.

On another sun-splashed day on the show's North Shore set — "it's very fun, despite the heat," Alvarado deadpans — the young actor bides his time between scenes, gamely receiving bear hugs from actress Kristy Wu, loafing on the hood of a truck with actor Johnny Pacar, talking shop with director MacHale, and hunting buried treasure with Watumull's 3-year-old daughter, Caitlin. Sometimes during the lunch break, he'll assemble members of the crew for a game of whiffle ball.

Once the cameras start rolling, however, Alvarado is all business.

"What's amazing is that he hits his lines every single time," Watumull says. "The director might ask him to change his intonation or something, but he's always prepared, and he always has the words perfectly."

Alvarado also dutifully answers reporters' personal queries, despite the fact that he'd clearly prefer to talk about the show and his cast mates.

"I think the show is doing well because it teaches stuff," Alvarado says. "It's fun, but it's not just fun. It teaches lessons in life."

In the series, Alvarado plays kid brother to Hallee Hirsh's well-intentioned but occasionally overbearing Daley. Usually overlooked until the crisis of the week reaches a boiling point, it is Alvarado's Lex who most often comes through with some gem of disaster-averting knowledge, gleaned from the mountain of books he's read.

Even friends and acquaintances from his school in California sometimes mistake the actor for the role.

"Sometimes people will come up and ask me about leeches," says Alvarado, referring to an episode from the first season in which Lex saves Daley from the slimy bloodsuckers by using a burning stick.

Alvarado worked his way through the usual child-actor path of print ads, TV commercials (including McDonald's and Ballpark Franks) and small-budget films. By the time he got his first regular acting gig with "Flight 29 Down," Alvarado already had figured out where his future lay.

"He's in his element," says father Rick Alvarado, sweeping his hand across a panorama of cameras and monitors. "He could be happy anywhere, as long as he's in front of the camera."

To preserve a sense of normalcy, Rick and Wendy Alvarado spend the entire three-month filming season living with their son in the show's North Shore dormitory.

They also accompany him on the set, where Rick, a manager and distributor for a communion-cup company, tends to his own business on a laptop computer. Like other parents who visit, the Alvarados are careful to be supportive without meddling with the production.

"Last year, (Allen) didn't know what to expect," Wendy says. "The cast members were all older, but they accepted him right away, and he built those relationships all year, because everyone kept in touch.

"He was bouncing off the walls because he couldn't wait to come back for Season 2," she said.

Alvarado's castmates apparently felt the same way.

"They're a family away from his real family," his mother says. "They all make time to hang out and talk with him. He'll go out and be active with the guys, or read with Kristy, or play poker with Lauren and Hallee, or play guitar with Johnny. He's learning piano from Corbin."

The Alvarados say they are aware of the problems many child actors face as they get older. Their preventive medicine includes healthy doses of the mundane. Allen, a math and science whiz, works with a tutor and does his homework before firing up the video-game console. He takes out the garbage and attends to other everyday chores, and he calls his grandparents and aunts several times a week.

While Alvarado's first regular TV job has been a thrilling (if occasionally taxing) ride for the family, Rick said he'd have no problem if Allen decides that acting isn't for him, after all.

"Whatever makes him happy," Rick said. "We won't force him to be what he doesn't want to be, but he's very determined to do this. I think he'll have a long career, whether it's in front of or behind the camera."

Reach Michael Tsai at mtsai@honoluluadvertiser.com.