Dorothy Dehner was born in Cleveland, Ohio in 1901. Her father died when she was about ten and the family moved to Pasadena, California in 1915. After the death of her mother and sister, she was raised by her mother's sister, Aunt Florence. Dehner was exposed to art as a child, receiving instruction in drawing and painting. She studied drama for a year at UCLA in 1922-1923 before moving to New York with the intention of pursuing a theatrical career. In 1925, she traveled alone to Europe, where she visited Italy, Switzerland, and France and where she began to draw seriously.
Upon her return to New York, Dehner enrolled in the Art Students League intending to study sculpture, but, uninspired by the work of William Zorach's sculpture class, ended up studying drawing with Kimon Nicolaides instead. In 1926, she met fellow artist David Smith in the rooming house they shared. At her suggestion, he too enrolled in the Art Students League. In 1927, they were married.
At the League, Dehner and Smith studied with the modernist painter, Jan Matulka, and befriended Weber and Thomas Furlong, through whom they met the Russian painter and theoretician, John Graham. Graham introduced them to the avant-garde art world and ended up having a profound influence on them both and their work. Around this time, they also befriended other young artists, such as Adolph Gottlieb, Mark Rothko, and Edgar and Lucille Corcos Levy. In 1929, after a visit to the Furlong's summer home in upstate New York, Dehner and Smith bought a farm in Bolton Landing, which became their permanent home in 1940 and was later named Terminal Iron Works. They spent eight months in the Virgin Islands, in 1931-1932, where Dehner painted abstract still lifes of shells and marine life. In the fall of 1935, they traveled to Europe, where they met up with Graham in Paris, spent five months in Greece, and toured the Soviet Union, with other stops along the way.
During her years at Bolton Landing (from 1940 to 1950), Dehner progressed in her work, producing a series of paintings titled Life on the Farm and embarking upon a series of abstract geometric drawings in ink and watercolor. In 1943, she had a joint exhibition with Smith at the Albany Institute of History and Art. Three years later, she participated in the annual exhibition of Audubon Artists and was awarded a first prize for drawing; and in 1948, she had her first one-woman show at Skidmore College.
Dehner left Bolton Landing in 1950 (she was divorced from Smith two years later) and returned to school, earning her degree from Skidmore College in 1952. She moved back to New York City, and supported herself over the next several years by teaching at various schools, including the Barnard School for Girls. She had her first solo exhibition in the city at the Rose Fried Gallery, and studied engraving at Stanley William Hayter's Atelier 17. At this point, Dehner started making sculpture, first experimenting in wax and then casting her wax sculptures in bronze. In 1955, she began working at the Sculpture Center, and from this point on, focused mainly on sculpture with occasional forays in drawing and print-making. In addition to works in bronze, she went on to create sculptures in wood (during the 1970s) and steel (during the 1980s).
In 1955, Dehner married the New York publisher, Ferdinand Mann. That same year, she joined the Willard Gallery, run by Marian Willard. She had her first exhibition of drawings there in 1955 (which led to a solo exhibition at the Art Institute of Chicago) and her first sculpture show there in 1957; she continued to show at the Willard Gallery regularly until 1976. Over the next several decades, Dehner's work was frequently exhibited in solo and groups shows at museums and galleries across the country, and was acquired for both public and private collections.
In addition to her art work, Dehner was also a published poet and writer. She wrote the foreword to the 1971 re-issue of John Graham's System and Dialectics of Art, and an essay on David Smith's "Medals for Dishonor," which was published in Art Journal in 1977. And two of her poems, "Past Tense" and "Two Lines," appeared in the journal Tracks in 1977.
Dehner continued to work into her nineties. She passed away in 1994.