Harpo was born on November 23, 1888, in Manhattan. The Marx children grew up on East 93rd Street off Lexington Avenue in a neighborhood now known as Carnegie Hill on the Upper East Side of the borough of Manhattan. The turn-of-the-century building that his brother Harpo called "the first real home they ever knew" was populated with European immigrants, mostly artisans.
Harpo's parents were Sam Marx (called "Frenchie" throughout his life) and his wife, Minnie Schoenberg Marx. Minnie's brother was Al Shean. Marx's family was Jewish. His mother was from East Frisia in Germany, and his father was a native of Alsace in France and worked as a tailor.