Jermayne MacAgy, designer of art exhibitions, museum director, and art professor, daughter of Worthington H. and Rose Kathryne (Corsila) Noble, was born on February 14, 1914, in Cleveland, Ohio. Her parents separated early in her childhood, and she was raised by her mother and stepfather, John H. Smart. Her stepfather stimulated her ambitions and encouraged her to keep up with her studies; although he never legally adopted her, she used his surname before her marriage. She received a B.A. in art history from Radcliffe College in 1935 and subsequently did two years of graduate study at the Fogg Art Museum. From 1937 to 1939 she continued her graduate studies at Western Reserve University, where she studied the philosophy and psychology of art under the guidance of Thomas Munro. She received her M.A. in 1938 and the following year earned her doctorate with a dissertation on the folk art of the Western Reserve.
Jermayne Smart began her career as an instructor in the education department of the Cleveland Museum of Art, where she worked from 1939 to 1941. On March 24, 1941, she married Douglas MacAgy; although they later divorced, she continued to use his name until her death. In August 1941 she began work as a temporary instructor in the education department at the California Palace of the Legion of Honor in San Francisco. There she emerged as a gifted innovator in museum education and exhibition design. She instituted a city-funded program in which museum educators presented slide lectures and installed mini-displays at area schools. She drew the public to the museum with more than 300 artfully designed exhibitions on subjects ranging from antique children's toys to Japanese folk art. In 1943 she became the youngest museum director in the country when she was appointed acting director, a position she held until director Thomas Howe returned from military service in 1946. MacAgy continued to work as an assistant director until 1955, when she accepted a position as director of the Contemporary Arts Museum in Houston.
During her four-year tenure as the Contemporary Arts Museum's first professional director, Jermayne MacAgy organized twenty-nine exhibitions, each accompanied by a catalogue. She presented a wide range of topics, many of which were unusual at that time, such as Yard Art (1957), Films 1948–58 (1958), and The Disquieting Muse: Surrealism (1958). She amplified the influence of these eclectic themes through her installations, which were designed to elicit aesthetic and psychological responses from the viewer. For example, The Trojan Horse: The Art of the Machine (1958) interspersed machine-inspired paintings and sculptures with diagrams, gears, screws, cogs, flywheels, and other gadgets, arranged on the walls and in space so that the viewer was enveloped in a mechanical environment. MacAgy's most successful exhibition for the CAM was Totems Not Taboo (1959), one of the most comprehensive exhibitions of primitive art organized in the United States by that time. The expense of her exhibitions strained the resources of the CAM, however, and her contract was not renewed in 1959.
With the help of Dominique and John de Menil, MacAgy established an art department at the University of St. Thomas in 1959. During her five years there she lectured and organized eleven exhibitions accompanied by catalogues. Her last exhibition, Out of This World, an exhibition of fantastic landscapes from the Renaissance to the present, opened after her death. Although she died prematurely, at age fifty, on February 18, 1964, her legacy lived on through the work of her followers, including the art dealers Katherine Swenson and Louise Ferrari, and through the impact of her exhibitions on Houston artists. MacAgy's mentor and protégée, Dominique de Menil, succeeded her as head of the art department at the University of St. Thomas and continued her tradition of innovative exhibitions. MacAgy's own collection, which ranged from sixth-century Greek animal sculptures to contemporary art by Joseph Cornell, Mark Rothko, Jim Love, and Forrest C. Bess, was donated to the University of St. Thomas, which subsequently featured her collection in a memorial exhibition, Jermayne MacAgy: A Life Illustrated by an Exhibition (November 1968–January 1969).