She was born in Istanbul, in 1936 as the third child of Mithat Yenen, an architect from Salonika and German Anneliese Rupp, who chose the name Aliye after marrying Yenen. She completed her education at Mimar Kemal Primary School and Ankara High School for Girls. After graduating from high school in 1952, she enrolled at Ankara University, Faculty of Language, History and Geography, Department of Archaeology. She met Özdemir Nutku, who was studying English Philology at the same university, and followed him to Gottingen in Germany in 1956. Nutku had received a scholarship and Soysal left her education incomplete. She took archaeology and theatre courses at Gottingen University.
Having returned Turkey in 1957 due to her pregnancy, she began working at the German Embassy. In those years, her writing appeared in Değişim along with those of Özdemir Nutku. Also, her stories and articles were published in various journals such as Dost, Yelken, Ataç, Yeditepe. She translated Andorra by Max Frisch and Mezar Bekçisi by Franz Kafka into Turkish. In 1958, she gave birth to her son, Korkut, who was autistic. The special attention and care needed for her son’s development and Özdemir Nutku’s departure for military service as soon as their return from Germany led to problems in their marriage, and eventually, they were separated.
The writer’s first story collection titled Tutuklu Perçem is published in 1962. She took part in the play "Zafer Madalyası", staged by Haldun Dormen at Ankara’s first private stage, Meydan Sahnesi. She later married her fellow actor in the play, Başar Sabuncu, in 1964. She began working at TRT, which was given autonomy in 1964, with the offer of Turgut Özakman, then the Head of Central Program Office. She was putting together adaptations from literature for various programs. She published her stories in some leading journals such as, Papirüs and Yeni Dergi between the years 1965 and 1969. She went to the Faculty of Political Sciences as a TRT reporter to interview Mümtaz Soysal and she was very much impressed by him. In those years, she wrote a play titled Venüslü Kadınlar. She got a degree in Archaeology in 1969. She gained renown within literary circles with her works Tante Rosa, published in 1968 and Yürümek in 1970. She broke up with Başar Sabuncu. Yürümek, which won an Achievement Award from TRT in 1970, is confiscated for being obscene immediately after the military intervention. The writer was arrested for political reasons after 12 March and was imprisoned for a short period. She had to leave her job at TRT. After having been arrested for the second time, she was temporarily sent to the region known as “Yıldırım Bölge.” She wrote her novel Bir Öğle Vakti here. Mümtaz Soysal, who is arrested on the eve of 12 March was in prison as well. Sevgi Soysal married Mümtaz Soysal at the military prison in Mamak in 1971.
After 2 months at the Central Prison, to which she was transferred in 1972, Soysal was exiled to Nevşehir for a brief time and later to Adana for three months. She gave birth to their daughters Defne in 1973 and Funda in 1975. She was one of the contributors of ANKA News Agency, which was founded by Altan Öymen with the encouragement of Haldun Simavi, bringing together many journalists forced to unemployment after 12 March. Her novel Şafak, which is a criticism of the 12 March military intervention through the experiences of a woman who is exiled in Adana, was published in 1975. Soysal got ill in the autumn of 1975 and was diagnosed with cancer. Her memoirs, which were serialized in the Politika journal, are collected in a book titled Yıldırım Bölge Kadınlar Koğuşu. Barış Adlı Çocuk, which includes the stories of her illness and the transformation of the country after 12 March, was published the same year. Sevgi Soysal died on 22 November 1976, without being able to complete her novel Hoş Geldin Ölüm, on which she has been working for some time. Her articles published in Yeni Ortam and Politika journals are collected in a book titled Bakmak.