Zeppo participated in the Marx Brothers' successful vaudeville acts, refining their comedic style and building a strong following. The brothers developed their routines through countless performances, honing their timing and improvisational skills.

Zeppo made his film debut in 'The Cocoanuts,' the Marx Brothers' first feature film adapted from their Broadway hit. While the film captured some of their stage energy, it was a learning experience for translating their comedy to the screen.

Zeppo starred in 'Animal Crackers,' another successful film adaptation of their stage show. His role as Horatio Jamison, although less outlandish than his brothers' characters, provided crucial support to the comedic mayhem.

In 'Monkey Business,' Zeppo continued his role as the straight man, often delivering lines that set up his brothers' jokes. His physical comedy skills were also evident in certain scenes.

Zeppo played Frank Wagstaff, the son of Groucho's character, in 'Horse Feathers.' This role further solidified his position as the handsome and relatively sane member of the family, contrasting sharply with his brothers' antics.

'Duck Soup' marked Zeppo's final film appearance with the Marx Brothers. While considered a masterpiece by many, its initial box office failure contributed to the brothers' temporary split. Zeppo's role, once again, was that of the level-headed foil to his brothers' chaos.