The son of Russian parents in Latvia, Baryshnikov entered Riga's opera ballet school at age 12. The success that he achieved there convinced him to devote himself to dancing. In 1963 he was admitted to the Vaganova ballet school (the training school for the Kirov (now Mariinsky) Ballet in Leningrad 【St. Petersburg】), where he was instructed by Aleksandr Pushkin. In 1966 he joined the Kirov Ballet (Mariinsky Ballet) as a soloist without having to serve the customary apprenticeship as a member of the corps de ballet. As the Kirov Ballet's premier danseur noble, Baryshnikov appeared in the leading roles in Gorianka (1968) and Vestris (1969), two original ballets that had been especially choreographed for him.

Baryshnikov was extremely popular with Soviet audiences, but he began to chafe at the official restrictions that were placed upon him as an artist, particularly the prohibition on his performance of contemporary foreign ballets. While on a dance tour in Toronto in June 1974, Baryshnikov defected and was granted asylum by the Canadian government. Soon thereafter he began a series of highly successful appearances before North American audiences. As a dancer, his great physical prowess and unsurpassed leaping ability enabled him to perform the most difficult combinations of steps with remarkable elegance of line.

In addition to his ballet career, Baryshnikov played a leading role as dancer and actor in the motion pictures The Turning Point (1977), White Nights (1985), That's Dancing! (1985), and Dancers (1987). He played a dramatic role in the Franz Kafka play Metamorphosis (1989) and appeared as a recurring love interest of lead character Carrie Bradshaw in the television series Sex and the City (2003–04).