In her memoir, The Liars' Club, poet and essayist Mary Karr recreated and reflected on her rugged and often traumatic childhood in an industrial town in East Texas. Karr chose not to reveal the name of her home town, but refers to it in her book by the fictional name of Leechfield. The work focuses primarily on events that took place between 1961 and 1963, when Karr was seven and eight years old, and the book contains the author's adult musings on her past and her family. In the course of the work, Karr describes mental illness, violence, neglect, and substance abuse. Her mother suffered from mental instability. Her father was a heavy drinker and a storyteller, an oil refinery worker who spent his leisure time at what many women in the small town called the "liars' club," the back room of the local bait shop, where men gathered to socialize and spin yarns. Jonathan Yardley of the Washington Post Book World called The Liars' Club "a beauty" and "a great pleasure to read." Louisa Ermelino described the work in People as "astonishing," and Michiko Kakutani in the New York Times lauded it as "extraordinary" and "one of the most dazzling and moving memoirs to come along in years." Molly Ivins, in her review for Nation, called the book "quite simply wonderful."

Reviewers have praised Karr's use of language, particularly her command of East Texas colloquialisms, but also the poetic quality of her prose. "Her most powerful tool is her language, which she wields with the virtuosity of both a lyric poet and an earthy, down-home Texan," maintained Kakutani, who added, "It's a skill used . . . in the service of a wonderfully unsentimental vision that redeems the past even as it recaptures it on paper." According to Cyra McFadden in the Los Angeles Times Book Review, Karr "has a flawless ear for the salty, folksy East Texas dialect that she learned at her daddy's knee. . . . The language of The Liars' Club crackles with energy and wit." Asserted Elizabeth Young in a review for New Statesman and Society, "The book's rhythm is deceptively oral, seemingly circuitous when it is tightly structured. One's attention never flags. Karr's control of the drawling East Texas demotic . . . is spectacular." Wrote Ivins: "I have always claimed that being a literate Texan is like being bilingual, and Mary Karr is a perfect example of that bilingualism. She can switch from Yeats to Coonass without a pause, from down-home similes about dog shit to Ezra Pound. . . . To have a poet's precision of language and a poet's gift for understanding emotion and a poet's insight into people applied to one of the roughest, toughest, ugliest places in America is an astounding event."

Karr's use of humor is another aspect of her work often lauded by critics. "This is such a captivating book, at once hilarious and heartfelt, that you don't have to believe every word to love it," stated McFadden. "The way some people are born with perfect pitch, Karr . . . is blessed with a sense of humor that allows her to see whatever happens to her, good, bad or terrible, as just one more example of chaos theory at work."

Sheila Ballantyne, writing in the New York Times Book Review, found a sense of anguish behind Karr's artistic achievement. "At times," the critic wrote, "it feels as if the book itself were trying to decide whether it can reasonably contain all that [Karr] needs to discover, and all that she needs to let go in order to become her own creation. . . . Not the least of her assets in this quest is her haunting, often exquisite phrasing of states of being and qualities of mind that resonate long after a page is turned." Ballantyne concluded: "In the end, it is her toughness of spirit, as well as her poetry, her language, her very voice, that are the agents of rebirth that accompany her on this difficult, hard-earned journey."

The Liars' Club spent nearly sixty weeks on the bestseller lists and sold more than half million copies in the U. S. The book's sequel, Cherry, deals with Karr's adolescence in the same small Texas town. The project proved difficult, Karr told Publishers Weekly, partly because "there's no language for talking about female adolescence. . . . I had to invent it; I wrote 500 pages and threw them away before I started approaching a voice that I thought was true." Another problem was the limitation of memory—with tongue-in-cheek, Karr has said that she was so immersed in drugs during that time that she can't remember what happened. Nevertheless, her narrative captures the simultaneously self-centered and insecure world of teenaged girls as they experience falling in love and a yearning for independence from family and home town.

In the New York Times Book Review, Sara Mosle wrote: "If The Liars' Club succeeded partly because of its riveting particularity, Cherry succeeds because of its universality. The first book is about one harrowing childhood, the second about every adolescence. Karr's talent doesn't depend on the specifics of her autobiography. She can turn even the most mundane events—a first kiss, an altercation with a school principal—into gorgeous prose." Kakutani likewise commented that Karr "proves herself as fluent in evoking the common ground of adolescence as she did in limning her anomalous girlhood." The critic continued: "As she did in The Liars' Club, Ms. Karr combines a poet's lyricism and a Texan's down-home vernacular with her natural storytelling gift. Some of her stories are nostalgic for a vanished time and place; some are scathing in their evocation of an insular world; some are just plain funny." Entertainment Weekly correspondent Lisa Schwarzbaum also concluded: "In this remembrance of blooming, Karr continues to set the literary standard for making the personal universal."

At age eleven, in the only journal Karr ever kept, she wrote that she wanted to publish books, "one-half poetry and one-half autobiography." Although she is better known for her memoirs, it was as a poet that she first established herself in the literary community. Her first volume of poetry, Abacus, was characterized by New England Review contributor Richard Katrovas as "among other things, a book of passionate friendship," treating women's issues and other personal concerns. Katrovas elaborated: "The sadness that films Mary Karr's vision seems not at all the milky sadness of melancholy, for she convincingly portrays a courage not to submit to her own darkness, acknowledging the terrors of a random universe and that the only stays against those terrors are soulfully construed meanings, the games we invent for the sake of private, fleeting, order." Karr's second poetry collection, The Devil's Tour, was also lauded by critics, who again noted Karr's ability to avoid excessive sentimentality and melodrama in her poems about the human condition. In his review in Poetry, David Barber asserted: "Avowedly unsentimental, Karr doesn't overcompensate by striking exaggerated poses of disabused wisdom or affecting mandarin disdain for the muddle of human relations. . . . Hers are the measured lamentations of a writer who will always side with the painful certitude over the wishful thought."

Critics have praised Karr's use of language in her poetry. A Publishers Weekly contributor noted particularly Karr's "delicate and meticulous control of detail" in The Devil's Tour, and Library Journal contributor Ellen Kaufman characterized the poems in The Devil's Tour as "movingly adept," applauding Karr's ability to write "natural-sounding formal meter." This blend of evocative language and emotional tone drew particular notice from Leslie Ullman in a Poetry review of the daring collection, Viper Rum. Ullman declared: "Mary Karr's third collection probes, without sentimentality or loss of vitality, autobiographical material she has handled in previous collections and in her celebrated memoir, The Liars' Club." Ellen Kaufman in Library Journal maintained that the work in Viper Rum is "confessional writing that conjures up the physical world." Ullman contended that the poems in Viper Rum "affirm human gestures towards life by highlighting them as gestures. . . . Karr peers beyond illusions of safety and is energized by the shadows out there, the persistent and unanswerable questions."

Reflecting upon her aspirations as an author, Karr told Publishers Weekly: "Public readings and the oral tradition [are] important to me. An aesthetic experience is fine, but unless someone is infused with feeling from a work of art, it's totally without conviction. My idea of art is, you write something that makes people feel so strongly that they get some conviction about who they want to be or what they want to do. It's morally useful not in a political way, but it makes your heart bigger; it's emotionally and spiritually empowering."