Helen Prejean her best-selling book, "Dead Man Walking" (1993), based on her experiences with two convicts on Death Row for whom she served as spiritual adviser before their executions. In her book, she explored the effects of the death penalty on everyone involved. The book was adapted as a 1995 film of the same name, starring Susan Sarandon and Sean Penn. It was also adapted as an opera, first produced in 2000 by the San Francisco Opera. Helen Prejean was born in Baton Rouge, Louisiana, the daughter of Augusta Mae (née Bourg; 1911–1993), a nurse, and Louis Sebastian Prejean (1893–1974), a lawyer.
Helen Prejean experiences with Sonnier and with the convict Robert Lee Willie. He had been sentenced to death after being convicted of kidnapping, murder in two attacks in May 1980. Sister Prejean also explored the effects of maintaining the death penalty on attorneys, prison guards, other prison officials, and the families of both convicted murderers and their victims. Prejean has worked with other men sentenced to death since then. In December 2010, Prejean donated all of her archival papers to DePaul University. In 1999, Prejean formed Moratorium 2000, a petition drive that eventually grew into a national education campaign, The Moratorium Campaign,