Born in New York City and raised in Lawrence, Kansas, Smith studied at Grinnell College in Iowa. Her career in the arts started in 1968 while an undergraduate summer intern at the Corcoran Gallery of Art in Washington D.C. The following year she was awarded a fellowship to participate in the Independent Study Program (ISP) at the Whitney Museum where she met Donald Judd and became interested in minimal art.
After graduation, she returned to New York City in 1971 to take a secretarial job at the Museum of Modern Art, followed by part-time assistant jobs to Judd and Paula Cooper in 1972. While at the Paula Cooper Gallery she wrote exhibition reviews for Artforum, and subsequently for Art in America, the Village Voice and other publications as well. She began writing for the New York Times in 1986.
Smith has written numerous essays for catalogues and monographs on contemporary artists, and wrote the featured essay in the Judd catalogue raisonné published by the National Gallery of Canada in 1975. She writes not only about contemporary art but about the visual arts in general, including decorative arts, popular and outsider art, design and architecture. In 2003 the College Art Association awarded her the Frank Jewett Mather Award for Art Criticism.