Born in Stuttgart, Germany to American parents, Agnes Pelton was a pioneering American modernist who spent most of her childhood in Switzerland and France.

At age 19, she graduated from the Pratt Institute in New York and later studied with Arthur Dow and her mother, Florence Pelton. Her early work was mostly portraits and representational subjects, but in 1925 she began to change to abstraction. Arthur Dow's influence led to her "Imaginative Paintings" of ethereal seeming figures expressing the moods of nature and the dichotomies between contemplation and animal impulse.

She began visiting the Southwest in the 1920s as a guest of Mabel Dodge, and became one of the leading voices for radical abstraction in New Mexico. Along with Raymond Jonson and William Lumpkins, she was part of a group of ten New Mexico painters who called themselves the Transcendental Painting Group, dedicated to radical abstraction in the 1930s when realism prevailed. However, there is no evidence she was in New Mexico at this time, but she carried on her crusade for modernism through correspondence with Raymond Jonson.

In 1923 and 1923, Pelton was a visitor to Honolulu, Hawaii, where she visited her cousins, Theodore and Mary Atherton Richards and painted portraits, still lifes, and Hawaiian landscapes including ohia, common trees, especially around Kilauea Volcano.

In 1931, she moved to California where she settled in Cathedral City and spent the rest of her career painting the West, especially surreal scenes of blooming desert. In 1995, the Palm Springs Desert Museum held a major retrospective of her painting.