Before her conversion, she had an abortion, but afterwards was a firm opponent of both abortion and contraception.
She got J. Edgar Hoover's attention as she associated with people like Leon Trotsky, and flirted with socialism and even anarchism. She founded the Catholic Worker newspaper in 1933. Her leftist credentials are impeccable:
- cited by Pope Francis in speech before Congress (just kidding)
- had love affairs and other relationships with prominent Communists (before conversion)
- asked the Church where were the works of mercy that comrades used to reach workers
- founded the Catholic Worker (CW) newspaper and movement
- admired Karl Marx and anarchist Peter Kropotkin
- Buddhist-curious Trappist Thomas Merton and radical priest Daniel Berrigan wrote for CW
- advocated absolute, uncompromising pacifism, opposing entry into WWII
- stood in picket line when workers at Catholic cemetery went on strike against Cardinal Spellman, involved in many strikes, e.g. with Cesar Chavez
- praised Karl Marx, Vladimir Lenin and Mao-Tse-Tung in 1951
- picketed the U.S. Atomic Energy Commission
- praised Fidel Castro in 1960
- praised Ho Chi Minh in 1970
- moved by visit to Kremlin where old colleague Jack Reed was honored with an inscription
- wrote that Che Guevara "laid down his life for his brothers" in 1970
- remained fascinated with Communism and anarchism
This is just a sample. Note that most of her fascination with the hard left was after her conversion.
Dorothy Day was a Benedictine Oblate. There is no suggestion that her Catholic faith was anything but genuine. She even wrote a book to answer the question "How can you be a Catholic?" that she would frequently hear. She did not, however, bother trying to separate her religion from her politics. (The Bear would observe few do.)
Most of what she did was as a writer and activist. She did begin a loose confederation of houses where volunteers gave food and shelter to poor people. It is impossible to say how much of this she was responsible for, although she did live out her days in voluntary poverty in one of the houses. It must be said, however, that she was primarily a woman of ideas and gestures: of writing and supporting causes.
As possibly the only Anarcho-Communist American candidate for sainthood, it was inevitable that Pope Francis would hold Dorothy Day up as an example. This is the type of Catholic Pope Francis likes, and the type of Catholicism he promotes. In charity, the Bear will assume that Dorothy Day was motivated by a genuine concern for the poor, that perhaps got mixed up with some unsound ideas of her time. However, her undying fascination with Communism and adoption of a Quaker notion of pacifism shows a questionable formation.
Dorothy Day herself said, "Don't call me a saint." Some of her followers today agree, saying that it would obscure the real nature of her work.
Source: various, but mostly Wikipedia article on Dorothy Day.