Cynthia Gregory was born in Los Angeles, California. Her parents encouraged her to take up dancing when she was a young child. She first appeared on the cover of Dance Magazine at age seven.
At age 14, she won a Ford Foundation scholarship to study with the San Francisco Ballet, where she quickly rose to soloist and then to principal dancer. In 1965, she joined American Ballet Theatre (ABT) in New York City. She became a prima ballerina known for her statuesque (6 feet tall en pointe) physique, strong dramatic presence, and performances in Giselle, Sleeping Beauty, Coppélia, Don Quixote, and La Sylphide, among others. She danced the first performance as Odette/Odile in David Blair's 1967 restaging of Swan Lake, a role always associated with her. She also danced in contemporary works, some of which were created for her. She left ABT in 1991 and performed as a guest artist with leading dance companies around the world. She now stages classical ballets, coaches, and gives master dance classes for dance companies. Her own choreographic works include a solo to Bach’s "Air on the G String," and a two-minute rock video for Campbell's Soup. Since 2008, she has been a member of the Board of Directors of The Isadora Duncan Dance Foundation. She has been married three times and has two children. She's the author of Ballet Is the Best Exercise (1986) and a children’s book, Cynthia Gregory Dances Swan Lake (1990). Her drawings have been exhibited at private and public art galleries and on dance posters and CD covers.