Plimack Mangold was born Sylvia Plimack in New York City, to a family of Jewish background. She is the daughter of Ethel (Rein), an office administrator, and Maurice Plimack, an accountant and businessman. She grew up in Queens, and attended the High School of Music and Art in Manhattan, after high school she was accepted into the program at Cooper Union in 1956. She continued her studies at Yale University and graduated with a B.F.A. in 1961. In the same year she married Yale classmate and fellow painter Robert Mangold.
After studying at Yale with William Bailey and others, Plimack Mangold worked as a representational painter. Her paintings in the early 1960s were paintings of floors, walls and corners, compositions where mirror images were also introduced, making the space more complex. In the 1970s she added trompe-l'œil elements such as metal rulers and masking tape along the borders of the images.
In the 1980s she introduced the images of the landscape to the canvas affixed by the image of masking tape. Eventually, the landscape image filled the entire canvas and focused on individual trees, their branches cropped so as to create the spaces between the limbs and branches of the trees. All the landscape paintings are done from observation. Even as the subject matter of Plimack Mangold's paintings has shifted, her work has always been based in perceptual realism, inviting viewers to observe from up close and mirroring her own process of observation.
Mangold received a grant from the National Endowment for the Arts in 1975. Her work has been the subject of solo exhibitions at the Museum of Fine Arts, Boston, the Neuberger Museum of Art at the State University of New York at Purchase, the Albright-Knox Art Gallery, and the Wadsworth Atheneum in Hartford, Connecticut, and is represented in the aforementioned museums in Boston, Hartford, and the Brooklyn Museum of Art.