Russian dancer and company manager of the Imperial Ballet in St. Petersburg, who re-created for several western European companies the many classical ballets that had been preserved in the Russian repertoire.

Trained at the St. Petersburg Imperial Ballet School, Sergeyev joined the company in 1894 and was promoted to soloist and régisseur, or stage manager, in 1904 and régisseur-général in 1914. He became unpopular with the dancers for what they considered his dictatorial control of the company, and he left Russia in 1918 with choreography for 21 ballets recorded in Stepanoff dance notation, a system used by the Imperial Ballet at the end of the 19th century. Since many of the classical ballets had not been consistently included in western European repertoires, Sergeyev was instrumental in re-creating for various companies such ballets as La Fille mal gardée, Giselle, Coppélia, Swan Lake, The Sleeping Beauty, and The Nutcracker.

Beginning in 1921, Sergeyev worked with Sergey Diaghilev's Ballets Russes, the Markova-Dolin company, the Ballet Russe de Monte Carlo, and the Metropolitan Opera Ballet, but principally with Sadler's Wells (now the Royal) Ballet and with the International Ballet, whose director, Mona Inglesby, inherited Sergeyev's notes after his death. The Stepanoff scores are now housed in the Harvard Theater Collection.