Lise Børsum was born in Kristiana (now Oslo), Norway, the daughter of composer Eyvind Alnæs and his wife Emilie Thorne. In 1930, she married Ragnar Børsum, a physician. During the German Occupation of her country in World War II, she joined the Norwegian Resistance movement and helped Jews escape deportation. In 1943, she was arrested by the Nazis, tortured in prison, and sent to the Ravensbrück concentration camp. She survived and after the war wrote several books on her experiences, including Fange i Ravensbrück (Prisoner in Ravensbrück, 1946) and Speilbilder (1947). She also published a book on Soviet concentration camps, Fjerndomstol Moskva, Fra dagens Berlin og Sovjets fangeleirer, in 1951. She was an original member of the Commission Internationale Contre le Régime Concentrationnaire, founded in 1950. She also worked as a freelance writer for the Norwegian newspaper Dagbladet. Her daughter Bente Børsum became an actress who has toured with a one-woman show called Min forestilling om mor (Mother) based on Lise's life.