Leonard "Chico" Marx was the eldest of the Marx Brothers. Marx used an Italian accent for his on-stage character; stereotyped ethnic characters were common with Vaudeville comedians.

Chico was a talented pianist. In the brothers' last film, Love Happy, Chico plays a piano and violin duet with 'Mr. Lyons'.

When their mother Minnie died, Chico became manager of the Marx Brothers. As manager he cut a deal to get the Marx Brothers a percentage of a film's gross receipts — the first of its kind in Hollywood.

For a while in the 1930s and 1940s Chico led a big band. Singer Mel Tormé began his professional career singing with the Chico Marx Orchestra.

He had a reputation as a world-class pinochle player. His brother Groucho said Chico would throw away good cards (with the knowledge of spectators) to make the play "more interesting." Chico's last public appearance was in 1960, playing cards on a television show, Celebrity Bridge. He and his partner lost the game, but it did not seem to bother him at all.