Dorothy Day, Obl.S.B. (November 8, 1897 - November 29, 1980) was an American journalist, social activist, and Catholic convert. Day initially lived a bohemian lifestyle before gaining fame as a social activist after her conversion. She later became a key figure in the Catholic Worker Movement and earned a national reputation as a political radical, perhaps the most famous radical in American Catholic Church history.

Dorothy Day was born on November 8, 1897, in the Brooklyn Heights neighborhood of Brooklyn, New York. She was born into a family described by one biographer as "solid, patriotic, and middle class". Her father, John Day, was a Tennessee native of Irish heritage, while her mother, Grace Satterlee, a native of upstate New York, was of English ancestry. Her parents were married in an Episcopal church in Greenwich Village. She had three brothers and a sister. In 1904, her father, who was a sports writer devoted to horse racing, took a position with a newspaper in San Francisco. The family lived in Oakland, California, until the San Francisco Earthquake of 1906 destroyed the newspaper's facilities and her father lost his job. From the spontaneous response to the earthquake's devastation, the self-sacrifice of neighbors in a time of crisis, Day drew a lesson about individual action and Christian community. The family relocated to Chicago.  Day's parents were nominal Christians who rarely attended church. As a young child, she showed a marked religious streak, reading the Bible frequently. When she was ten she started to attend Church of Our Saviour, an Episcopal church in the Lincoln Park neighborhood of Chicago, after its rector convinced her mother to let Day's brothers join the church choir. She was taken with the liturgy and its music. She studied the catechism and was baptized and confirmed in that church in 1911.  Day was an avid reader in her teens, particularly fond of Upton Sinclair's The Jungle. She worked from one book to another, noting Jack London's mention of Herbert Spencer in Martin Eden, and then from Spencer to Darwin and Huxley. She learned about anarchy and extreme poverty from Peter Kropotkin, who promoted a belief in cooperation in contrast to Darwin's competition for survival. She also enjoyed Russian literature in university, especially Dostoevsky, Tolstoy, and Gorky. Day read a lot of socially conscious work, which gave her a background for her future; it helped bolster her support for and involvement in social activism.  In 1914, Day attended the University of Illinois at Urbana-Champaign on a scholarship. She was a reluctant scholar. Her reading was chiefly in a Christian radical social direction. She avoided campus social life and supported herself rather than rely on money from her father, buying all her clothing and shoes from discount stores. She left the university after two years and moved to New York City.

Where did they move after the San Francisco Earthquake?
The family relocated to Chicago.