Louise Hay, was born to a poor mother who married Hay's violent stepfather. When she was about five, she was raped by a neighbor. At fifteen she dropped out of high school without a diploma, became pregnant, and on her sixteenth birthday gave up her newborn baby girl for adoption. She moved to Chicago, where she worked in menial jobs, before moving in 1950 to New York. At this point, she changed her name and began a career as a fashion model. She was successful at this, working for Bill Blass, Oleg Cassini, and Pauline Trigere.

In 1954, she married Andrew Hay, but after fourteen years of marriage Louise was devastated when Andrew left her for another woman.

Hay said that she found the First Church of Religious Science on 48th Street, which taught the transformative power of thought. Hay revealed that here she studied the metaphysical works of authors like Florence Scovel Shinn and the Religious Science founder Ernest Holmes.

In the early 1970's Hay became a Religious Science practitioner. In this role she led people in spoken affirmations meant to cure their illnesses. She also became popular as a workshop leader.

She studied transcendental meditation with the Maharishi Mahesh Yogi at his university in Fairfield, Iowa.

In 1977 or 1978 she found she had cervical cancer, and she concluded that its cause was her unwillingness to let go of resentment over her childhood abuse and rape. She refused medical treatment, and began a regimen of forgiveness, therapy, reflexology, nutrition, and occasional enemas, and claims she rid herself of the cancer. She declared that there is no doctor left who can confirm this story, but swore that it is true.

In 1976 Hay wrote a small pamphlet, which came to be called "Heal Your Body." This pamphlet was enlarged and extended into her book You Can Heal Your Life, which was published in 1984. As of February 2008, it is still on the New York Times best sellers list.

Around the same time she began leading support groups for people living with H.I.V. or AIDS that she called Hay Rides. These grew from a few people in her living room to hundreds in a large hall in West Hollywood. Her work with AIDS patients drew fame and she was invited to appear on "The Oprah Winfrey Show" and "Donahue" in the same week in March, 1988.

You Can Heal Your Life immediately landed on the New York Times Best Sellers List. More than 35 million copies are now in print around the world in more than 30 languages and has been made into a movie. Louise Hay established Hay House Publishing. It is the primary publisher of books and audio books by Deepak Chopra and Doreen Virtue, as well as many books by Wayne Dyer.

In addition to running her publishing company, Hay runs a charitable organization called Hay Foundation that was established in 1985.