Walther was the daughter of an officer. She soon discovered her comedic talent and passion for the theater and studied after visiting the school Christianshavns 1953-1956 elevskole at the Privatteatrenes, the drama school of the New Theatre Copenhagen.
After a first film appearance in 1956, it was known in 1957 for her role as Tjenestepige in Annelise Reenbergs film Tre piger fra Jylland. Although it in the next three decades in many movies and television series in two ( Huset på Christianshavn ( "Oh, these tenants " ), from 1970 to 1977, and Smuglerne, 1970) was involved, it was left to the theater - and here particularly the Copenhagen ABC Teatret - always faithful.
Kirsten Walther became popular, especially known in Germany at the side of Ove Sprogøe, Poul Bundgaard and Morten Grunwald in the Danish film series The Olsen Gang, which was directed by Erik Balling. Here she played the role of Yvonne, the naive and constantly nagging wife of crooks Kjeld, which became more and more over the course of the films to the female lead.
After her last film appearance in Olsen tied over all Bjerge (1981 ) Three years later she retired permanently from acting back in order to devote themselves to their family. On February 19, 1987 Kirsten Walther died unexpectedly at the age of 53 years of a heart attack. About the death of Walther's many rumors circulating in Denmark. She found her final resting place on the Vedbæk Kirkegård on the northern edge of Copenhagen.
After Walther's death it seemed impossible to continue the Olsen Gang series. Not until 1998 that the last part of this popular series was filmed without her.
Kirsten Walther was married since September 26, 1959, the director and producer Ruben Palle Wolfsberg (* 1931). She adopted together with her husband in 1966 a two- year-old boy from Greenland.