Ragnheiður Jónsdóttir was the daughter of a teacher from a small coastal town in the south west, qualified as a teacher herself, and studied theory of education in England and Scandinavia. She sat on the committee of the Rithöfundafélag Íslands (Icelandic Writers’ Association) from 1958 to 1960 and chaired the association from 1964 until she died. She was married, had two children, and wrote many of her novels during illness and from her sickbed.
She made her debut as a children's and teenage writer with the first of her eighteen titles in 1934. In her novels for adults, she dealt with taboo subjects such as frigidity, abortion, anorexia, and melancholy. Her writing developed aesthetically from realism to critical modernism, and her style is characterised by minimalism and dramatic presentation. Her first novel for adults, Arfur, 1941, a multi-protagonist, fast-paced novel, was given a promising review.
Her main work, the four-volume novel Úr minnisblöðum Þóru frá Hvammi, 1954-1964, follows Þóra's fight for education and an independent life, while obligation leads to increasing depression. The poetic novel Mín liljan fríð, 1961, about an anorexic young girl at the turn of the century thematizes the development of the female artist's identity and opportunities for expression. The posthumously published novel Villieldur, 1967, a publication in defence of a woman who has killed her husband, is a modernist, fragmented, and ambiguous text.