Lee Strasberg (November 17, 1901 – February 17, 1982) was an Academy Award-nominated American actor, director, and one of the best-known acting teachers in American theater and film. He cofounded, with director Harold Clurman, the Group Theatre in 1931, which was "America’s first true theatrical collective." In 1951, he became director of the non-profit Actors Studio, in New York City, considered "the nation's most prestigious acting school". He was the chief proponent of "Method acting" from the 1920s until his death in 1982, and according to acting author Mel Gussow, "he revolutionized the art of acting and had a profound influence on performance in American theater and movies."

Acting historian Jeremy Butler writes, "The one man most responsible for 'the Method' becoming the dominant technique of screen acting in the United States was Lee Strasberg: popularizer of the term 'the Method'." He refined, synthesized, and eventually disseminated the teachings of Stanislavski to his Actors Studio students. From his base in New York, he trained several generations of theatre and film's most illustrious talents, including Anne Bancroft, Dustin Hoffman, Montgomery Clift, James Dean, Marilyn Monroe, Julie Harris, Paul Newman, Patricia Neal, Sally Field, Jane Fonda, Franchot Tone, Gene Wilder, Geraldine Page, Ellen Burstyn, Al Pacino and director Elia Kazan.

Strasberg explained his "Method" through his class lectures and writings: "The two areas of discovery that were of primary importance in my work at the Actors Studio and in my private classes where improvisation and 'affective memory,'... the process of contacting one’s memories of emotions in order to channel them into a role... It is finally by using these techniques that the actor can express the appropriate emotions demanded of the character" Although Marlon Brando also studied "Method" acting, but under Stella Adler, Elia Kazan directed him in A Streetcar Named Desire (1951) and On the Waterfront (1954,) where he came to epitomize "Method" acting in the public’s mind. Kazan also directed another student, James Dean, in East of Eden (1955), for which Kazan and Dean were nominated for Academy Awards. Dean once wrote that Actors Studio was "the greatest school of the theater the best thing that can happen to an actor." In more recent years, directors like Sidney Lumet have intentionally used actors skilled in Strasberg's "Method", such as Al Pacino, Paul Newman, Dustin Hoffman and Anne Bancroft.