After her father's death in 1907, Eleanor Mellon moved to New York City and enrolled in classes at the Art Students League. Her teachers included Victor Salvatore, Robert Aitken, and Adolph A. Weinman. She spent two summers at Lanesville, Massachusetts, under the tutalege of Charles Grafly. After World War I, Edward McCartan encouraged her to study the sculpture of the Italian Renaissance, the results of which are evident in a number of her works.
Mellon gained immediate notice when she began exhibiting her work at the National Academy in 1921 (see below). Among the awards she earned there were the Helen Foster Barnett Prize of 1927 for Janice (cat. no. 198). Her portrait bust of the young Benjamin Kreiton, which was shown at the Academy in 1926 (cat. no. 166) and again in 1939 (cat. no. 3), won a bronze medal from the Society of Washington Artists. In later years, Mellon turned to the design and execution of religious sculptures, examples of which can be found in the Cathedral of Saint John the Divine, New York, and at Brookgreen Gardens, South Carolina.
Mellon served as secretary of the National Sculpture Society from 1936 to 1940 and as assistant treasurer of the National Academy. She was a member of the National Association of Women Painters and Sculptors. She retired in 1977.
Her bronze figurine of Iris, now lost, was presented to the Academy as her diploma work on November 6, 1950.