Claire Millman was born in New York City on December 24, 1917 to Russian-borm William Millman and Anna Lechter Millman. At some point she began using the last name of Mahl for her professional identification. Her formal art education began in the 1930s at the National Academy of Design, where she studied alongside Lee Krasner, and at the Art Students League with Harry Wickey, Charles Locke, and Thomas Hart Benton. In Benton's class she met Jackson Pollack who encouraged her to attend the workshop of Mexican artist David Alfaro Siqueiros, where she would become part of the "inital nucleus" of his Experimental Workshop in New York in 1936 until going to work in the WPA-FAP. During the 1940s Mahl worked at the New York atelier of Fernand Leger and in the 1950s studied with David Park at the San Francisco Art Institute.

In the late 1930s Mahl worked for the New York City WPA Art Project where she produced over 30 separate images, some in color.

Mahl began exhibiting in the 1940s starting in New York City, and in 1947 she won the ACA Gallery award for a one-woman exhibition. In San Francisco in the 1950s and 1960s she showed at the Key Gallery and the King Ubu Gallery, and in 1963 was given an exhibition at the California Palace of the Legion of Honor. In the 1970s she showed at the Green Mountain Gallery, NY 1973; Wilmington Museum Downtown Gallery, Delaware, 1976; Kathryn Markel and Robert Freidus galleries, NY, and the University of Northern Illinois at De Kalb, 1977. In 1984 her work was featured by the Rutgers Women Artists Series, New Brunswick, New Jersey, and in 1987 she had her first painting show at the June Kelly Gallery, NY. A second show followed in 1988 as did a show at the Sheldon Ross Gallery, Birmingham, Michigan. Mahl's work has been featured in numerous group shows including the King Ubu Gallery commemorative exhibition at the Natsoulas-Novelozo Gallery, Davis, California, January, 1989. Additional group shows include the Self Portrait: Tangible Consciousness, held at Rutgers University, 1987; Prints by Women Associated American Artists, NY, 1986, and the Inaugural Exhibition, New Museum of Contemporary Art, NY, 1983.

From early in her career Mahl formed an interest in book arts and teaching. She began making small books in the 1940s, and while in California in the 1950s founded Artists' View magazine; in New York in the late 1960s she founded the Children's Underground Press. She taught at the Marian Hartwell School of Design, San Francisco, 1950-56; Brooklyn College, NY, 1970-74; the Creative Women's Collective, NY, 1974; the Metropolitan Museum, Visiting Artists, Children's Program, NY; the Chicago Art Institute, 1977, and the College of Staten Island, NY, 1980-88. She was the recipient of three MacDowell Colony Fellowships, 1945, 1977 and 1979; and Tiffany and Gottlieb Foundation Grants, 1980 and 1985 respectively.

Among those institutions with work on paper by Claire Mahl are the Metropolitan Museum of Art, the Museum of Modern Art, the Whitney Museum of American Art, the Brooklyn Museum, the New York public Library, and the Franklin Furnace Archives, New York, and the Library of Congress, Washington, DC. Claire Mahl died on August 5, 1988.

Claire Millman Mahl was married twice and can be found listed as Claire Glick and then Claire Moore. Claire Millman Mahl Moore died in New York on August 5, 1988