Sonja Hauberg grew up on a country estate in northern Zealand and later in Skovshoved, studied comparative literature at the University of Copenhagen, and during her studies published poems, short stories, and articles. She was part of the circle attached to the literary magazine Vild Hvede and was a member of the Unge Kunstneres Klub. In 1945 she married for the second time, this time marrying the painter Richard Mortensen. Their son Finn Hauberg Mortensen wrote about his mother in Danske Digtere i det 20. århundrede, 1981. She died at the age of twenty-nine of typhoid, which she contracted during a writers' congress in Finland.
Her investigation of a mother fixation in her debut novel Hvad vil du mig?, 1942, shows the author to be a promising psychological realist. Her novel about growing up, Syv år for Lea, 1944, about a girl losing her childhood paradise in the country, the grind of upper secondary school, and the adolescent experience of meaninglessness stoked a debate and became a classic. She also wrote the novel April, which is experimental in terms of its form and full of symbolism and was published posthumously in 1961. A common feature of her novels and her dramatic work Ebbe Skammelsøn, 1945, is that they each depict a woman torn between two men in her expectations of love.