So I’m standing in the 9:30 Club’s men’s room, trying desperately to block out the frattish loudmouth who’s simultaneously encroaching on my personal space, hollering into his cell phone, and taking aim at a urinal cake. I’m running through the usual litany of gun-shy meditations—leaky faucets, Super Soakers, spawning salmon—but Mr. Chatty’s errant elbow and booming conversation are making me seriously rethink those last three Rolling Rocks. “Hey, I’m at the 9:30 seeing a show,” the multitasking tinkler shouts. “Shelby Lynne? Shel-by Lynne. She’s kinda like Bonnie Raitt. You’d like her. She’s good. She rocks.” After endless discussion about post-show revelry, Mr. Chatty finally slips the Nokia into a shirt pocket and leaves the bathroom without washing either hands or phone.

It could have been worse, I guess: He could have droned on with hyphen-ridiculous descriptions of Miss Lynne, such as Sheryl Crow-meets-Dusty Springfield-meets-Jim Beam or Tammy Wynette-meets-Bonnie Parker-meets-Caesar’s Palace. He could have detailed some of her hellish bio: While the family was living in charmingly podunk Frankville, Ala., Dad shoots Mom, then Dad shoots himself—all with a 17-year-old Shelby looking on. And there could have been lengthy deliberation on those well-documented paramour problems: married fast, divorced fast, oh-how-unlucky in love. In fact, had Mr. Chatty known much of anything about the most potential-fueled prospect on the roots-rock horizon, I probably would have missed that badass encore.

I Am Shelby Lynne is technically the singer-songwriter’s sixth album, but the straightforward title—and the tsunamic waves of recent print-media hype (accompanied by glossies of Lynne in various stages of undress)—confirms that the new recording is, in fact, her first real record. Produced by Crow cohort Bill Bottrell, Shelby Lynne is a hard-slap departure from the five Nashville discs she made while miserably trying to become the next Shania Twain. Although her sister, popular trad-country singer Allison Moorer, opted to stay put in the country capital and do her damnedest to thin the surge of crossover blood, the 31-year-old Lynne, on the verge of a serious mental meltdown, hopped a plane to Palm Springs to make the record that would save her soul. Like that, she said goodbye to the Wrangler-weary waif crooning about Hallmark love, and just as quickly, she revealed a hard-drinkin’, hard-smokin’, twice-arrested (stealing cars, getting kicked off planes) troublemaker with a fallen-angel alto and penchant for tough-luck lyrics. Shelby Lynne instantly became the hip hungover confessional—all parts swooning ’60s soul, jangly roots-rock, and midtempo cool-jazz ballads—that your office mates were demanding you buy. Spare the hyperbole, and what you have is both a good “debut” album that gives every indication that the follow-up will be great and an enigmatic artist who deserves all her candy-coated hoopla.

Dressed in a sleeveless black shirt, a thick black bracelet, and her trademark black leather pants, the 5-foot-1 Lynne, her neatly coiffed shoulder-length blond hair the only physical reminder of her Grand Ole Opry past, took the 9:30 Club stage with a cocky smirk and a swagger to match. In greeting a Wednesday evening crowd that managed to fill three-quarters of the joint, Lynne—still feeling out her little-bit-country, little-bit-rock-‘n’-roll persona—seemed musically out-of-sorts at first. Backed by six hulking lugs—an all-male posse that she’d been playing with for just three weeks—Lynne’s crystalline voice, which can go from whisper to wail without losing that achin’-heart sweetness, was smothered initially by her overbearing backing boys. “Your Lies,” which opens Shelby Lynne with a lusty spat between overwrought Dusty in Memphis strings and a tortured guitar, was muddled by an anxious band and Lynne’s straining to reach the front row. But the problems didn’t last long: Once the raggedy It Girl racked her Telecaster, positioned herself centerstage with just the mike, and took to singing the hell out of the set list, she properly backed up all that buzz.

With the exception of two crowd-pleasing covers—a sublime reading of John Lennon’s “Mother” that seemed to shush just about every murmur in a 10-block radius and a boot-stomping version of “one of my favorite songs,” “Wichita Lineman”—Lynne followed the track order—and the arrangement—of the new album. As perhaps the best summation of the sweet-and-sour singer, “Life Is Bad” read like a Poe-worthy nightmare (“Taste the stench of livin’ on thin dimes and a dream/Opening an ear to a painful silent scream”) but played like a hell-raisin’ honky-tonk party. The tandem of “Thought It Would Be Easier” and “Gotta Get Back” were built with summery shuffle-beats and syrupy slide guitar; the former features the singer staring at the phone and wondering what went wrong, and the latter offers a blue-sky chorus and the perfect soundtrack for a convertible cruise.

And as Lynne got more familiar with her material, she got all the chummier with the audience. “Anybody got a beer?” she purred after the barroom breakdown of “Life Is Bad”; and wouldn’t you know it, just like that, a dewy Bud lifted from the up-front mob and met the lips of the singer. “I wrote this about everybody in the room—including me and everybody on the stage,” she said, segueing into the next song, the what-the-fuck R&B anthem “Why Can’t You Be?” As the night cruised along, the hard-livin’ hostess high-fived a few guys, flirted with a few girls, and accepted a bouquet of roses from a fan who knew the words better than she did. She dusted off a slew of rock poses worthy of Joan Jett—pumped fists, flirty sneers, punctuating kicks, playful rubdowns of soloing bandmates—all the while straying further and further from her perfect-posture country doppelganger.

But the night’s best wild-child move she saved for last: Lynne encored with “Black Light Blue,” a last-call torch tune stripped down to a low organ moan and Lynne’s pained, twisting croon. As soon as the last word slowly pulled away from her mouth—”blue”—she spat, “That’s it. I’m outta here,” and tossed the mike to the ground like the best punk poet. The rude feedback popped and echoed as the crowd—including a blessedly silenced Mr. Chatty—started searching helplessly for a few more hyphens. CP