Dorothy Day was born in Brooklyn, New York, and raised in San Francisco and Chicago. She was born into a family described by one biographer as "solid, patriotic, and middle class". Her father was a Southerner of Scotch-Irish background, while her mother, a native of upstate New York, was of English ancestry. Her parents were married in an Episcopal church located in Greenwich Village, a neighborhood where Day would spend much of her young adulthood.
Initially Dorothy lived a bohemian life, with two common-law marriages and an abortion, which she later described in her semi-autobiographical novel, The Eleventh Virgin (1924)—a book she later regretted writing. She had been an agnostic, but with the birth of her daughter, Tamar (1926–2008), she began a period of spiritual awakening which led her to embrace Catholicism, joining the Church in December 1927, with baptism at Our Lady Help of Christians parish on Staten Island. In her 1952 biography, The Long Loneliness, she recalled that immediately after her baptism, she made her first confession, and the following day, she received communion. Subsequently, Day began writing for Catholic publications, such as Commonweal[ and America.
The Catholic Worker movement started with the Catholic Worker newspaper, created to promote Catholic social teaching and stake out a neutral, pacifist position in the war-torn 1930s. (See The Catholic Worker: The Aims and Means of the Catholic Worker.) This grew into a "house of hospitality" in the slums of New York City and then a series of farms for people to live together communally. She lived for a time at the now demolished Spanish Camp community in the Annadale section of Staten Island. The movement quickly spread to other cities in the United States, and to Canada and the United Kingdom; more than 30 independent but affiliated CW communities had been founded by 1941. Well over 100 communities exist today, including several in Australia, the United Kingdom, Canada, Germany, the Netherlands, the Republic of Ireland, Mexico, New Zealand, and Sweden. She was also a member of the Industrial Workers of the World ('Wobblies').
Her devotion to her church was neither conventional nor unquestioning, however. She alienated many U.S. Catholics (including some clerical leaders) with her condemnation of Falangist leader Francisco Franco during the Spanish Civil War; and, possibly in response to her criticism of Cardinal Francis Spellman, she was pressured by the Archdiocese of New York in 1951 to change the name of her newspaper, "ostensibly because the word Catholic implies an official church connection when such was not the case".
In 1971, Dorothy was awarded the Pacem in Terris Award. It was named after a 1963 encyclical letter by Pope John XXIII that calls upon all people of good will to secure peace among all nations. Pacem in Terris is Latin for 'Peace on Earth.' Day was accorded many other honors in her last decade, including the Laetare Medal from the University of Notre Dame, in 1972.
She died on November 29, 1980, in New York City.
Dorothy Day was buried in Cemetery of the Resurrection on Staten Island, just a few blocks from the location of the beachside cottage where she first became interested in Catholicism. She was proposed for sainthood by the Claretian Missionaries in 1983. Pope John Paul II granted the Archdiocese of New York permission to open Day's "cause" for sainthood in March 2000, thereby officially making her a "Servant of God" in the eyes of the Catholic Church.