Rita Kernn-Larsen was born in Hillerød, Denmark, on January 1, 1904. In 1924 she travelled to Oslo to visit her sister, where she attended the State Drawing School between 1924 and 1925. Upon her return to Copenhagen in 1926 she enrolled at the Art Academy (1927–29); however, disappointed by its teaching methods, Kernn-Larsen left for Paris in 1929. In the French capital the artist became a prominent pupil of Fernand Léger (1930–31) and met her future husband, the Jewish-born journalist and art dealer Isaac Grünberg, whom she would marry in 1940. Kernn-Larsen returned to Denmark in 1934 and that same year she had her first solo exhibition at the Kunsthandel Chr. Larsen, Copenhagen.

Her work was compared to that of Pablo Picasso, Léger and Georges Braque. Also in 1934 she met the Danish Surrealist group, befriending the artists Elsa Thoresen and Vilhelm Bjerke-Petersen. Simultaneously, she developed her skills as a magazine illustrator in publications such as Politikens Søndagsmagasin, Social-Demokraten and Hjemmet Søndag. From 1935 onwards she exhibited with the Surrealists in Copenhagen, Oslo, Lund, London and at the International Surrealist Exhibition in Paris (1938). Having met in Paris in 1937, where the artist then lived, Peggy Guggenheim gave Kernn-Larsen a solo exhibition entitled Exhibition of Surrealist Paintings by Rita Kernn-Larsen, at Guggenheim Jeune in May 31–June 18, 1938. Her works were included in two other group exhibitions at Guggenheim Jeune, also in 1938.

The artist, who had travelled to London specifically for the opening of her one-woman exhibition, was compelled to stay there as the war broke out. In London she attended meetings and participated in exhibitions of the London Surrealist Group while admiring the work of the Belgian artist Paul Delvaux. In 1944 her daughter Danielle Rose was born. At the end of the Second World War the artist moved to Saint Jeannet, in southern France, where she lived until 1992. After the war, Kernn-Larsen moved away from Surrealism towards an art based on nature and abstraction. In the years 1949 and 1950 she illustrated several children books; during the 1960s her work became fully non-figurative and she experimented with pottery, ceramics and collage. In 1986 she participated in the Venice Biennale and in 1995 she had an extensive retrospective exhibition at the Randers Kunstmuseum, Copenhagen. Kernn-Larsen died on April 10, 1998, in Copenhagen, Denmark.