ummo was born Milton Marx in 1897. He was one of the first brothers to be involved in the family act. As the group evolved through their vaudeville origins, Gummo was always present. As the Marx Brothers developed their comedy styles, Gummo served primarily as the straight man for the antics of Groucho, Harpo, and Chico. Gummo was nicknamed for his gumshoe way of sneaking up on people.

In 1918, as the group was gaining in popularity, Gummo stepped out. He felt he lacked the performing skills of his brothers, and decided to join the army and do his part in World War I. In 1934, when Zeppo quit the act and became an agent, Gummo joined him as his partner. Gummo died of natural causes April 21, 1977.