Birgit Keil was born in Kowarschen (today Kovárov) in the Sudetes region. She studied classical dance at the ballet school of the Württembergische Staatstheater Stuttgart, from which she was accepted into the corps de ballet of the Stuttgart Ballet in 1961. Her outstanding talent soon won her a scholarship to the Royal Ballet School in London, where she spend a year polishing her technique. Upon her return to the Stuttgart company in 1963, she was appointed a soloist and in later years first ballerina of the Stuttgart Ballet by the company director John Cranko.
As a member of the Stuttgart Ballet she gained international acclaim during worldwide tours with the company and often invited as a guest she became "the German Ballerina", dancing with Richard Cragun, Rudolf Nureyev and Mikhail Baryshnikov. She danced leading roles in all the company's productions of the classic and the modern repertoire. She inspired choreographers as Cranko, MacMillan, Wright, Teteley, Kylian, Neumeier, Spoerli, Scholz, van Manen, Feld and Haydée to create ballets especially for her. In 1980 she was granted the honorary titel "Kammertänzerin". Since 1968 she has been both in a private and professional partnership with Vladimir Klos, principal dancer of the Stuttgart Ballet from 1972 to 1997.
In the fall of 1995 Birgit Keil finished her active stage career with a magnificent farewell gala at the Staatsoper Stuttgart. At that time she initiated the dance foundation carrying her name, together with the Milanese Machesa Maddalena Mina di Sospiro. Since March 1997 Birgit Keil teaches at the Academy of Dance, University of Music and Performing Arts, Mannheim, and was given the title of a Professor by the prime minister of Baden-Württemberg. In July 1997 she became director of the Academy of Dance and with the beginning of the season 2003/04 she will in addition take over the direction of the ballet company of the Badische Staatstheater Karlsruhe.