Muni left Warner Brothers studio, where he was King of the Lot, in 1940 in order to free lance.
Muni once appeared as the Mystery Guest on an episode of the game show What's My Line?
Muni is buried in the Hollywood Memorial Cemetary in Hollywood, CA.
Muni and James Dean are the only actors to ever receive Academy Award nominations for their first and last movie appearances.
Muni himself considered Robert Donat to be the best actor in Hollywood.
Muni was one of six actors to win an Academy Award nomination for Best Actor in his screen debut and the only one who later won. The other five actors are: Alan Arkin, James Dean, Orson Welles, Montgomery Clift and Lawrence Tibbett.
Muni was the first actor to win an Oscar for portraying a real life person (Louis Pasteur).
During his live appearance in the Playhouse 90 production of The Last Clear Chance, Muni wore an earpiece and had his lines fed to him from off-stage.
Muni suffered from a rheumatic heart condition his entire life.
Muni was married to the former Bella Finkel from 1921 until his death in 1967.
Muni was 5 feet, 10 inches tall and weighed 165 lbs.
Muni loved to play the violin in his spare time.
Muni retired from acting in 1959 after completing The Last Angry Man.
Muni won a Tony Award in 1955 for his performance in the Broadway play Inherit the Wind. When the play was filmed Spencer Tracy played Muni's role.
Muni has a star on the Hollywood Walk of Fame located at 6435 Hollywood Boulevard.
According to Hollywood lore, Muni despised the color red and would fly into a rage when he saw a woman wearing a red dress in his presence.
Muni's final Academy Award nomination came in 1959 for The Last Angry Man.
Early in his career, Muni was billed by the studio as the New Lon Chaney.
Muni played a Chinese peasant in 1937's The Good Earth.
The fourth time was the charm for Muni when he won an Academy Award for Best Actor in 1939 for The Story of Louis Pasteur.
Muni received a third Academy Award Best Actor nomination in 1937 for The Life of Emile Zola. He didn't win but co-star Joseph Schildkraut won for Best Supporting Actor.
Muni was nominated for a second Best Actor Academy Award in 1932 for I Am a Fugitive From a Chain Gang.
The 1932 gangster film Scarface made Muni a star playing a character based on Al Capone. When Scarface was remade in 1982 Al Pacino played Muni's role.
Muni received an Academy Award for Best Actor in his film debut in 1929's The Valiant.
Muni's first Broadway role in the play, We Americans, was also the first time he acted in an English speaking production.
Muni was billed as Muni Weisenfreund when he acted in the Yiddish theatre.
Muni made his stage debut at age 12 playing an 80 year old man.
Muni's parents were actors in the Yiddish theatre in New York.
Muni's family emigrated to the United States in 1902.
Muni: I won't go up in a plane but if a play crashes I'll jump into the next one that comes along and take it for a spin.
Muni: I think a star is what you call actors who can't act.