Birgit Keil was born in Kowarschen. She was trained as ballet dancer in Bad Kissingen and in Stuttgart at the ballet school of the Staatstheater Stuttgart.She studied in London at the Royal Ballet School for one year on a scholarship. In 1961, she became a member of the company Stuttgart Ballet, in 1963 she was appointed soloist by John Cranko. She performed major parts of classical as well as modern ballet, as a partner of dancers such as Richard Cragun, Rudolf Nureyev and Mikhail Baryshnikov. Choreographers John Cranko, Eliot Feld, Marcia Haydée, Jirí Kylián, Kenneth MacMillan, Hans van Manen, John Neumeier, Uwe Scholz, Heinz Spoerli, Glen Tetley and Peter Wright created choreographies for her.  She was known internationally as “die deutsche Ballerina” (The German Ballerina), dancing at the Paris Opéra, La Scala, with the American Ballet Theatre, the Royal Ballet and the Vienna State Opera, among others.

Keil retired from the stage in 1995. She has been director and professor of the Akademie des Tanzes (Academy of Dance) at the Hochschule für Musik und Darstellende Kunst Mannheim, teaching classical ballet, repertory, variations and pas de deux. She is convinced that a classically trained dancer is able to dance in a wide range of styles.From 2003, Keil has been director of the ballet ensemble of the Badisches Staatstheater Karlsruhe in Karlsruhe, called Staatsballett Karlsruhe from 2013