Once crashed a Hollywood costume party at the home of Marion Davies, dressed as Kaiser Wilhelm II. He had to hitchhike to get home and ended up being arrested by Beverly Hills police on charges of vagrancy, illegal entry, escaping from jail in Gloversville, New York, impersonating Kaiser Wilhelm II, and impersonating Harpo Marx.
One of only two Marx Brothers to play a recurring role in their films (not counting when they used their own names). He played the role of "Pinky" in both Horse Feathers (1932) and Duck Soup (1933).
Recreated the mirror scene from Duck Soup (1933) in an episode of "I Love Lucy" (1951).
Served as the basis for the character Banjo in the long-running comedy "The Man Who Came to Dinner" by George S. Kaufman and Moss Hart. The play had one of its most memorable productions at the Bucks County Playhouse in Pennsylvania, where Kaufman played Sheridan Whitside (the character based on critic Alexander Woollcott, Hart played Beverly Carlton (the character based on Noel Coward, and Harpo played Banjo, speaking his first lines on stage in over twenty years.
Son of Sam Marx and Minnie Palmer.
The character of Banjo in George S. Kaufman and Moss Hart's play "The Man Who Came to Dinner" is based on Harpo.
Unmade-up and out of costume, the resemblance between Harpo and his brother Chico Marx was extraordinary. On the TV game show "I've Got a Secret" (1952), Chico once appeared in Harpo's wig and costume, with the "secret" "I'm Pretending To Be Harpo Marx (I'm Chico)" and fooled all the panelists -- including Groucho Marx.
Was cousin of Sadie Marks - better known as Mary Livingson; brother-in-law of Benjamin Kubelsky, aka Jack Benny.
Was seldom recognized when out of character because he was almost completely bald.
When he trained himself in the harp, he later learned that he did it the wrong way. However, when he became famous, many musicians came to him to learn his method of harp playing.