Why is this man smiling?

By now, the story of how Dan Tyminski came to sub for George Clooney’s unschooled larynx on “I Am a Man of Constant Sorrow” is old news. Yet the low-key singer/guitarist never seems to tire of explaining his role in the fictional-crowd-favorite-turned-real-life-hit from the Grammy-nominated O Brother, Where Art Thou? soundtrack.

“They had yet to cast George’s voice, so it just worked out that I was there when they needed someone. I sang a version at the audition that was completely different than the one we ended up recording,” says Tyminski. “It was just good fortune that I was in the right place at the right time.”

For the last 12 months or so, the Vermont native has been swept up in the hype surrounding the soundtrack to the Coen Brothers’ Depression-era comedy/drama. The album — which features newer artists like Alison Krauss and Gillian Welch alongside such country vets as Emmylou Harris and regional legends Ralph Stanley and the Cox Family — is arguably the best thing to happen to bluegrass since “Dueling Banjos.” But where that scene-stealer from Deliverance was long on novelty appeal and short on stylistic breadth, O Brother, Where Art Thou? digs deeper into the bluegrass canon while debunking its quaint hillbilly stigma.

“Sorrow” helped O Brother become the top-selling country album of last year. It also helped Tyminski earn a passel of Country Music Association and International Bluegrass Music Association awards. And when Grammy nominations were announced earlier this month, O Brother received the nod in a number of categories, including album of the year, best soundtrack and best country collaboration for “Sorrow” (sung by Tyminski, Harley Allen and Pat Enright — aka the Soggy Bottom Boys). Tyminski’s lead vocals on “Sorrow” are just sophisticated enough — but not so much so as to sand away the tune’s plainspoken Appalachian grit.

“The song makes you feel when you hear it,” says Tyminski. “I don’t think there was anything about the subtle intricacies of how we played it, or that it was such an intelligent, well-put-together song. It’s just a very raw, good-feeling, gutsy song.”

Tyminski has spent the better part of his career with Union Station, playing the more rugged, traditionally minded big brother of sorts to band leader Alison Krauss’ delicate, more pop-minded waif. Raised in the heart of Vermont’s Green Mountains, Tyminski grew up in a household immersed in the music of Ernest Tubb, Hank Williams and other old-time country icons. He was in grade school when his older brother introduced him to the guitar and mandolin. A devotion to such bluegrass notables as Del McCoury, Ricky Skaggs and Tony Rice followed in short order.

Tyminski taught himself to play both instruments before moving on to the banjo. And by the time he realized his technique was unorthodox, it was too late to turn back. “I ended up teaching myself — backward,” Tyminski recalls with a laugh. “The sounds made sense if you closed your eyes and listened, but I have a style that’s unique to me. When I tried to [play the banjo] the right way, I could only do it at a third of the speed.”

A teenage Tyminski made the leap into professional strumming as the banjo player in the Green Mountain Bluegrass Band before joining the Lonesome River Band, where his vocal and mandolin skills also came in handy. But it was soon after he fell in with Union Station that Tyminski’s rep as session player soared. Throughout the ’90s, he worked with Vince Gill, Randy Travis, Dolly Parton, Clint Black and other superstars. So it’s no wonder he relocated to Nashville. Somehow, Tyminski managed to find time to record a pair of bluegrass solo albums, including 2000’s Carry Me Across the Mountain, which he toured behind last year.

He’s been dubbed a “reluctant frontman” more than once, but Tyminski doesn’t come off like a guy who loathes the spotlight — just someone who prefers not to actively court it. And while any talk of financial reward for his work on O Brother, Where Art Thou? is greeted with an uncomfortable silence, to say he’s stunned by his good fortune would be an understatement.

“By far my craziest year was this past one,” says Tyminski. “It’s so cool to see bluegrass be the hip thing. For me it’s always been that. When I hear people thank me for bringing bluegrass to the people, I feel like smacking them and saying, ‘Hey, this is such a collective effort.’ I was so lucky to be such a small part of that thing that I’m still scratching my head trying to figure out how it all works.”

Dan Tyminski performs with Alison Krauss and Union Station as part of the Down From the Mountain tour Sun., Jan. 27, at the Atlanta Civic Center, 395 Piedmont Ave. Show time is 8:30 p.m. $36-$71. 404-249-6400. www.ticketmaster.com.’’??

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