Marya Hornbacher was born in Walnut Creek, California but raised in Edina, Minnesota from the age of nine. Her parents, Jay and Judy Hornbacher, both worked as professional theatre actors and directors; her mother also worked as a school administrator. According to her first autobiography, Wasted, Hornbacher was an only child and became bulimic at age nine and developed drug and alcohol problems by age thirteen. At age fifteen, she was accepted into the prestigious arts boarding school Interlochen where she developed Anorexia.

The summer following her first year at Interlochen she was hospitalized for her eating disorder and then moved in with her father's ex-wife in Northern California. While there, she met her future husband, Julian Daniel Beard, but her eating disorder steadily worsened and she was re-hospitalized after Christmas. She was released in February but readmitted again after only two weeks. Eventually her parents sent her to Lowe House, a residential treatment hospital for adolescents with severe, long-term mental problems.

After her release that summer, she enrolled in the University of Minnesota and started writing for the local paper. At the age of eighteen, despite her continued eating disorder, she signed out of treatment. In the fall of 1992, she entered college at American University in Washington D.C. Her eating disorder rapidly worsened and by the winter she had dropped to fifty-two pounds. On a visit home to her parents, she was admitted to the ER and given one week to live.

Though Hornbacher survived her ordeal, she has been left with many physical ailments as a result, including osteoporosis, a heart murmur, and infertility. Her second autobiography, Madness, also describes a near fatal incident of cutting but Hornbacher herself seems unclear about whether or not this was an intentional attempt at suicide.

Hornbacher married Beard in 1996, but they divorced after the success of Wasted. The marriage, and eventual divorce, is also discussed in Madness where she attributes the nuptial failure in part to problems with drugs and alcohol, and largely to her ill-managed bi-polar disorder.

Marya received a Master's Degree from the New College of California. Her second book, The Center of Winter, published in 2005, received excellent reviews, and her second memoir, Madness: A Bipolar Life, was published in 2008.

She has now been sober for over five years and lives in Minneapolis with her husband Jeff Miller; their cats Shakespeare and T.S. Eliot; and their miniature dachsunds Milton and Dante. Hornbacher writes full-time, working at her home in Minneapolis. She was recently honored with a major award for music journalism, for her profile of jazz great Oscar Peterson. She still publishes occasional journalistic pieces, as well as short fiction and poetry.