Julius Marx was born on October 2, 1890, in the Manhattan borough, of New York City, New York. Marx stated that he was born in a room above a butcher's shop on East 78th Street, "Between Lexington & 3rd", as told to Dick Cavett in a 1969 television interview. 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" (in his memoir Harpo Speaks) was populated with European immigrants, mostly artisans.
Marx's family was Jewish. Groucho's mother was Miene "Minnie" Schoenberg, whose family came from Dornum in northern Germany when she was 16 years old. His father was Simon "Sam" Marx, who changed his name from Marrix, and was called "Frenchie" by his sons throughout his life because he and his family came from Alsace in France. Minnie's brother was Al Schoenberg, who shortened his name to Al Shean when he went into show business as half of Gallagher and Shean, a noted vaudeville act of the early 20th century. According to Groucho, when Shean visited he would throw the local waifs a few coins so that when he knocked at the door he would be surrounded by adoring fans. Marx and his brothers respected his opinions and asked him on several occasions to write some material for them.