The One, the Only... Groucho is a documentary that celebrates the life and legacy of Groucho Marx, the legendary comedian, actor, gameshow host and master of quick wit.
| Actor | Role |
|---|---|
 Groucho MarxSelf (archive footage) | Self (archive footage) |
 David SteinbergNarrator | Narrator |
 Dick CavettSelf | Self |
 Bill CosbySelf | Self |
| GGeorge FennemanSelf | Self |
| JJohn GuedelSelf | Self |
 Marvin HamlischSelf | Self |
 Jack LemmonSelf | Self |
 Richard LewisSelf | Self |
 Art LinkletterSelf | Self |
| MMiriam MarxSelf | Self |
| NNat PerrinSelf | Self |
 Gloria StuartSelf | Self |