Believe him or not

Kevin Costner has a new family, a new production company, and a new film with a far-fetched story that he says will deliver the magic

In "Swing Vote," Kevin Costner (with Madeline Carroll) plays Bud Johnson, an irresponsible single dad whose vote will decide a presidential election. (YOON S. BYUN/GLOBE STAFF)

His green eyes don't actually sparkle.

On this muggy July morning in Boston, Kevin Costner is focused on trying to rub the sleep out of them. He is bearded and slightly scruffy - the GQ version of his trailer-dwelling, fishing-cap-wearing character in the new movie, "Swing Vote," opening Friday. The actor reveals that he has been up most of the night along with his wife, Christine Baumgartner, giving cold baths and undivided attention to their feverish 14-month-old son, Cayden.

Cayden has no clue that Daddy needs his rest to look good for early morning movie-star duties. Not that Costner cares a lick about appearances.

"When they cry like that, all you can think of is, OK, pull their sickness into me. I'll take it," says the 53-year-old Oscar winner, whose three children by a previous marriage are all in their 20s, and who also has an 11-year-old son by Pittsburgh/Osterville socialite Bridget Rooney.

Costner's been in show business far too long to pull any punches about his priorities. Though he quickly follows with a line about how media interviews have their place in the world, too, you know he would rather be upstairs comforting the toddler he never thought he'd have this late in life. And he knows you wouldn't have it any other way.

The appeal of Kevin Costner has always been his square-shaped ordinariness, if ordinary can even be used to describe a quietly cocky California native who is Hollywood handsome (tired eyes and all) and successful enough to own sprawling homes in Santa Barbara and Aspen, and a casino in Deadwood, S.D. He is known for playing the sympathetic everyman of underrated character, whether his playground is Westerns ("Silverado," "Dances with Wolves," "Open Range"), sports movies ("Field of Dreams," "Bull Durham," "Tin Cup," "For Love of the Game"), crime stories and romantic thrillers ("The Untouchables," "No Way Out," "JFK," "The Bodyguard"), or expensive, post-apocalyptic critical flops ("Waterworld," "The Postman").

In "Swing Vote," Costner revisits the kind of movie he was once adored for. He plays New Mexico factory worker Bud Johnson, an irresponsible single father who finds himself at the center of an unprecedented political circus when a presidential election comes down to his one deciding ballot. Don't spend too much time questioning whether that scenario could actually happen, even with the combination of polling-place errors and Electoral College gymnastics conjured on film. This movie isn't a civics lesson, Costner says; it's "an American comedy, very Capra-esque" - basically in keeping with both the best and worst of his filmography.

"Swing Vote" director Joshua Michael Stern ("Neverwas"), who co-wrote the film with the equally unknown Jason Richman ("Bad Company"), agrees that the premise requires some suspension of disbelief. "Logistically it cannot happen, but something close to it can happen," Stern said by phone from Los Angeles. As proof, both director and leading man point to Florida, where legend has it that the 2000 election ultimately hinged on a few hundred votes. This screenplay is not much more of a leap, they argue, and even if it were, the idea of individual power being undervalued and too often squandered in America is no leap at all.

If any actor knows the importance of standing tall despite the odds, it's 6-foot-1-inch Costner. He's the guy whose film resume famously begins with being edited out of "The Big Chill," and whose signature credits - including "Field of Dreams" (partially filmed in Boston), "Bull Durham," and "Dances with Wolves" - were mostly movies that no one wanted to make. His professional heroes are men like Gary Cooper, Jimmy Stewart, and Steve McQueen. Costner used to be compared to them regularly. But recent years have seen a string of mostly forgettable titles ("Message in a Bottle," "Dragonfly," "The Upside of Anger," "Rumor Has It," "The Guardian"), and now some people question whether the name Kevin Costner can really "open" (as in generate significant box office for) a big-screen release any more.

"Because I own movies, I know what bankable is. And my movies are bankable," Costner insists. "But when you say 'open up a movie,' movies are made for different audiences. 'Upside of Anger' was not a movie designed for any big demographic. Maybe the best question is: Can you deliver a movie? I feel like I can deliver a movie - what it's supposed to be."

Critics may disagree. His fans may even disagree. But Costner has been dictating his own definitions of success ever since he launched Tig Productions to make the thee-hour "Dances with Wolves," boldly thumbing his nose at studio wisdom and focus groups nationwide. "Swing Vote" is the first release by the actor-filmmaker's newest production company, Treehouse Films, and he says he plans to use the nascent brand for several pet projects he expects to direct and star in over the next few years. These include a World War II drama, yet another Western, and an "urban, sexy-violent journey that's kind of cool," he says, which is at least a better description than when he pronounced Madonna's concert "neat" in the documentary "Truth or Dare."

Also coming, in 2009 from New Line Cinema, is "The New Daughter" directed by Luis Berdejo. It's Costner's first foray into horror, if you don't count last year's creepy psychological thriller, "Mr. Brooks," or his notorious bludgeoning of accents in 1991's "Robin Hood: Prince of Thieves" and the 2000 Kennedy memoir, "Thirteen Days."

There may even be room on his dance card for touring with his suddenly center-stage roots-rock band, Modern West, which supplied several songs for the "Swing Vote" soundtrack and stands in for his character's Willie Nelson tribute band, the Half-Nelsons, in the film.

But if all that sounds like a spray of creative buckshot in search of a hit, the veteran entertainer insists it isn't part of any long-term comeback master plan.

"I'm quintessentially an American actor," he says. "I just try to take you into different genres and try to make myself seamless and believable."

He claims that even the timing of "Swing Vote," which seems so obviously positioned to benefit from being released in a presidential election year, was not premeditated. In fact, he says, it's hard to know whether the film will be helped or hurt by comparisons between the over-the-top campaign tactics of its fictional candidates (played by Kelsey Grammer and Dennis Hopper) and the real life campaigns of John McCain and Barack Obama.

America is at a crossroads, in need of a true "giant" to lead it, the movie pleads in its most impassioned speech. And maybe Kevin Costner, who wrote those words for his character, is at a crossroads, too.

His 12-year-old "Swing Vote" costar, Madeline Carroll, recalled in a separate Boston interview how excited she was when she found out she'd be playing his daughter on film. She considers herself a huge fan. The punch line is that Carroll hasn't seen very many of Costner's movies; she reveres him mostly for spawning Waterworld: The Live-Action Stunt Show at Universal Studios' Hollywood theme park.

It feels like a long time since Costner made a movie that lodged stubbornly in our brains, good or bad. Maybe, fingers crossed, Treehouse Films is his way back to being a cinematic giant.

Janice Page can be reached at jpage@globe.com. For more on movies, go to boston.com/ae/movies/blog.