What 1941 film directed by Preston Sturges follows a film director who goes undercover as a tramp?

The 1941 Preston Sturges film about a director who goes undercover as a tramp is Sullivan's Travels.

Joel McCrea plays John L. Sullivan, a successful Hollywood comedy director who wants to make a serious social drama about suffering and poverty. Believing that he needs firsthand experience, Sullivan disguises himself as a tramp and sets out to travel among poor and working people.

The journey becomes a satire of Hollywood’s claim that artists can understand hardship simply by observing it. Sullivan discovers that his privileged experiment cannot reproduce the dangers faced by genuinely poor people, and he becomes entangled in violence, imprisonment, and exploitation. Veronica Lake plays a struggling actress who joins him.

The film’s central argument is more complicated than its premise: entertainment may not solve social problems, but laughter can offer real relief to people enduring them. The title alludes to Gulliver’s Travels, while Sullivan’s proposed serious film is titled O Brother, Where Art Thou? A common mix-up is with Sturges’s The Great McGinty, another 1940s satire, but it follows a corrupt politician rather than an undercover director.