[1][2][3] After attending Sofie Bernhoft's school, Myhrvold spent a year studying theater in Copenhagen.

Already as a young woman, Myhrvold often played older women, whom she portrayed with weight and credibility, including the mothers in Leo Tolstoy's The Power of Darkness and Selma Lagerlöf's The Emperor of Portugallia as well as Tale in Olav Duun's Medmenneske (Fellow Man).

With a broad sense of humor, she also played genuine Oslo types such as Gurina-Neger in Oskar Braaten's Ungen (The Child) and Dobbelt-Petra in the same author's Den store barnedåpen (The Great Christening).

[4] Myhrvold was a teacher at the Norwegian Theater's student school, which she led from 1947 to 1949.

She also worked to establish the National Academy of Theatre (Norwegian: Statens teaterhøgskole), which opened in 1953 and where she taught for a few years.