Dorothy May Day was born on November 8, 1897 at Brooklyn to an Anglican Day family. As a young journalist, Dorothy engaged in the systematic 1910s–1920s New York bohemian-radical-intellectual life — including a common-law marriage with Forster Batterham and the famous 1927 conversion to Catholicism following the birth of her daughter Tamar Teresa.
On May 1, 1933, at Union Square in New York City, Dorothy and French-immigrant philosopher Peter Maurin distributed the first issue of the Catholic Worker newspaper (1 cent per copy) — the institutional founding of the Catholic Worker Movement.
The Catholic Worker Movement established the Houses of Hospitality across the United States — the hospitality-based systematic Catholic care of the poor, the homeless, and the Depression-and-post-Depression working-class.
Dorothy undertook the systematic Catholic pacifism — famously opposing the World War II, the Vietnam War, nuclear weapons, and the Cold War militarism.
Dorothy died at Maryhouse Catholic Worker in New York City on November 29, 1980 at the age of 83.
The cause of canonization was opened March 16, 2000 by the Archdiocese of New York.