Theatrical director, teacher, and actor Constantin (or Konstantin) Sergeyevich Stanislavsky (or Stanislovski) was born Constantin Sergeyevich Alekseyev in Moscow in 1863. His system for training actors has had a profound effect on the process of acting in the 20th century; known as "the method", it stresses the psychological and emotional aspects of acting and is founded on the idea that an actor's responsibility is to be believable and believed.

Stanislavsky came from a wealthy background; his family had a thriving business producing gold and silver thread. They had also founded a theatrical group, the Alexeyev Circle, which Stanislavsky joined as a boy of fourteen. Though he continued to work at his family's business, he also became a principal actor with the troupe. Throughout his teen years he grew as an actor, and began to produce and direct plays and become involved in all aspects of the theatre. He took the stage name Stanislavski at 25 to escape the mark of the prodigal son well-funded by his family. He was apparently a very tall man (about 6'6") and a heavy smoker, though he disapproved of heavy drinking and loose morals.

In 1897 Stanislavsky had a historic and epic meeting with Vladimir Nemirovich-Danchenko; over 18 hours the two shared ideas which would come to fruition in 1898 with the founding of the Moscow Art Theatre. The two men would remain associated with that theater for the rest of their lives. There Stanislavsky achieved renown for his productions of operas and of Chekhov's plays, though Chekhov himself despaired of these stagings, at one point wailing to the press that "Stanislavsky ruined my play!" The Moscow Art Theatre reflected social concerns on stage, and after the 1917 Revolution Lenin personally protected Stanislavsky, impressed by his social conscience and commitment to social justice.

Stanislavsky stressed ensemble acting rather than star-driven productions. His method required actors to portray the emotional truth of roles: they should reach within themselves to find an emotional space that resonated with the character they were going to play, a break from previous modes which dictated that actors should leave themselves behind when they took on the character they were to play. In later life he created a series of physical exercises which he believed would help an actor bridge the gap between life and the stage. He travelled around the world teaching his method, and it was the inspiration for New York's Actor's Studio, which has had as members such illustrious personages as Marlon Brando and Sidney Poitier.

Stanislavsky wrote a number of books on his methods, including An Actor Prepares, Building a Character, and Creating a Role, as well as an autobiography, My Life in Art. He died in 1938, but his name lives on, linked with that of his collaborator, in the Stanislavsky and Nemirovich-Danchenko Musical Theatre in Moscow.