American stage and film actor acclaimed for his portrayals of noted historical figures.

Born to a family of Polish Jewish actors, Muni began appearing on stage with his parents while still a young child. After the family's immigration to the United States, he played in Yiddish stock companies on the East Coast and joined New York's Yiddish Art Theater in 1918. As a young actor he mastered the art of makeup—a skill that served him well throughout his film career—and often played characters older than his years. During the 1920s he was a star of the Yiddish stage; this helped him land his first Broadway role in We, Americans (1926). He was lured to Hollywood to appear in The Valiant (1929) and received an Academy Award nomination for his first motion picture role.

Muni's reputation as a prominent stage actor prevented Hollywood from molding him into a marketable image or into a typical big-screen leading man. It also allowed him the luxury of script approval—a concession granted to very few actors during the days of the studio system. Consequently, Muni's film roles were diverse and generally superior to most Hollywood fare. He became celebrated for his in-depth portrayals of prominent historical figures as well as for films with important social themes. His noted works from the 1930s included Scarface (1932), I Am a Fugitive from a Chain Gang (1932), Black Fury (1935), The Story of Louis Pasteur (1936), The Good Earth (1937), The Life of Emile Zola (1937), and Juarez (1939). Whatever the role, Muni did extensive research into the character, studying dialects and reading every literary work available on his subject. He also made an effort to disguise his own well-known features under extensive makeup to create a physical representation of the subject.

Nominated five times for Academy Awards, Muni was named best actor for his performance in The Story of Louis Pasteur. He won a Tony Award for the stage version of Inherit the Wind (1955) and received an Oscar nomination for his final film, The Last Angry Man (1959).