Carrie Underwood just spent several hours sitting in Audio Productions - a Music Row radio and TV production facility - doing interviews with radio stations across the country, but she looks fresh and relaxed as she prepares for her final chat of the day. She talks with the engineer about how excited she is to hear Miranda Lambert's new CD, "Revolution" (listen free here). And when someone offers to give her a copy, Underwood sweetly protests, "Oh, no, I'm going to buy it."

Carrie Underwood Song Premiere: "Temporary Home"

It's that combination of girl-next-door charm and a killer set of pipes that has made Underwood the most successful artist to come out of "American Idol" in any genre. Since winning the fourth season of the Fox competition, Underwood has released two albums, the 2005 "Some Hearts" (listen free here), which has sold 6.8 million, according to Nielsen SoundScan, and the 2007 "Carnival Ride" (listen free here), which has sold 2.9 million. She's won four Grammy Awards and numerous other accolades including three Country Music Assn. (CMA) female vocalist titles and three Academy of Country Music female vocalist honors. Last spring, she took home the ACM's entertainer of the year award, becoming only the seventh woman in the show's 42-year history to earn that accolade.

With such impressive accomplishments just four years into her career, one might expect Underwood to feel a little pressure before the Nov. 3 release of her new Arista Nashville album, "Play On." Instead, she radiates a quiet confidence.

"I feel like the second album had the most pressure for me," she says, acknowledging that she felt the first one had a shot at succeeding because of her built-in "Idol" audience. Then it exceeded expectations. "It kept going and kept going and kept going and the next thing it was like triple-platinum and quadruple-platinum and five-times-platinum and it was like 'Oh, my gosh!' "

Looking svelte in a black sweat shirt dress with a red belt, red bracelet and red Marc Jacobs flats, 26-year-old Underwood is the epitome of casual chic-but don't mistake laid-back for unambitious.

"I want to be somebody in the music business, not just somebody that [people say], 'Oh, yeah, five years ago she won that. Where did she go?' So making ["Carnival Ride"] was pretty stressful, but on this one I feel like I'm home," she says. "I'm in the music business. When people mention names like Kenny Chesney and Keith Urban and Brad Paisley, sometimes my name is in there too."

Sony Music Nashville chairman Joe Galante feels Underwood's confidence has translated into a more personal body of work on "Play On." "It already has scored a victory because it represents growth for her sonically, vocally and from a lyrical standpoint," he says, seated in a conference room at Sony Music Nashville's headquarters. "We had more fun on the last album with some of the things that she was writing. With this, there is a balance between the fun Carrie and also one that is revealing more about herself, her views about life."

NEXT: Carrie talks about opening up on "Play On"