Lately it's been a little weird for Johnny Staats. No longer can he just drop off a package, collect a signature and go on his way. Now clients hound him for his autograph. "You that celebrity?" they ask. Staats's answer is always the same: "No, I'm just the UPS man."

But it's not that simple. It's truer to say that Staats, 30, is the UPS man whose high-energy mandolin-picking is the talk of Nashville and whose first album, Wires and Wood, out in April, may be, if word of mouth is any indication, the biggest thing to hit bluegrass music since Lester Flatt and Earl Scruggs. "In his hands the mandolin soars and glides, pops and hisses," says blue-grass star Tim O'Brien.

The son of a gravel-company foreman and a homemaker, Staats grew up near Vienna, W.Va., immersed in the music of the hills and hollers. While other kids played sports, he practiced his mandolin—and his guitar—up to eight hours a day.

After he married Lori, his childhood sweetheart, in 1989—they have two daughters, Jessica, 9, and Hannah, 1—Staats shelved plans of becoming a music teacher and went to work for UPS. Meanwhile he played at festivals throughout Appalachia. It was at one of those, in 1997, that Ron Sowell featured him on National Public Radio's show Mountain Stage, of which Sowell is director. "It was," he says, "the most original music I'd heard in years."

Since then, Staats has been working on his album, with some of blue-grass music's greatest stars, including O'Brien and Sam Bush, sitting in. But he's not planning to give up his day job. "I like this work," he says. "Besides, there's no guarantee in the music business."