Astrid Hjertenæs Andersen was born and grew up in Horten and Borre in Vestfold. Her father worked in the navy. As a young woman, she attended the Hallings secretarial and journalism school and worked as a typist and journalist from 1934 to 1942. She was married to the painter Snorre Andersen.
Astrid Hjertenæs Andersen, who made her debut with a collection of poems entitled De ville traner, drew her inspiration and motifs from antiquity. In her earlier poems she often corrected and criticized artistic interpretations of women within a Modernist tradition. Her key works include Skilpaddehagen (P), 1950, Pastoraler (P), 1960, and Frokost i det grønne (P), 1964. Her collected works, Samlede dikt, were published in 1985.