[2] Her work was exhibited at galleries and museums worldwide and widely published in Life, Rolling Stone, The New Yorker, New York Times, and Vanity Fair.

[5] After graduating, she worked briefly in the Philadelphia city planning department,[5] then returned for a master's degree in photojournalism at the Annenberg School for Communication at the University of Pennsylvania, which she received in 1964.

[1] In 1966[4] or 1967,[1] she moved to New York City, where over the next several years she photographed demonstrations in opposition to the Vietnam War, the women's liberation movement, transvestite culture, and Times Square, developing a sensibility, according to one writer, "away from mainstream society and toward its more interesting, often troubled fringes".

Mark was also a special stills photographer on movie sets, shooting production stills of more than 100 movies, including Arthur Penn's Alice's Restaurant (1969), Mike Nichols' Catch-22 (1970) and Carnal Knowledge (1971), Francis Ford Coppola's Apocalypse Now (1979), and Baz Luhrmann's Australia (2008).

[12] She published 21 books of photographs and contributed to publications that include Life, Rolling Stone, The New Yorker, New York Times, and Vanity Fair;.

[3] Mark was transparent with the subjects of her photography about her intent to use what she saw in the world for her art, about which she has said "I just think it's important to be direct and honest with people about why you're photographing them and what you're doing.

The film was based on Mark's photographic essay "Streets of the Lost" made on assignment for Life magazine with writer Cheryl McCall.

[18] She was the associate producer and still photographer for the feature film American Heart (1992), starring Jeff Bridges and Edward Furlong, and directed by Martin Bell.

[5] Mark died on May 25, 2015, in Manhattan, aged 75, of myelodysplastic syndrome, a blood illness caused by bone marrow failure.