A poet from a small town inherits a fortune, becomes disgusted by people in New York, and plans to give it to the unemployed as small farms.
A financier dies and leaves $20,000,000 to his nephew Longfellow Deeds (Gary Cooper). Attorney John Cedar (Douglass Dumbrille) takes poet Deeds to New York after he plays the tuba for his friends. Cedar wants power of attorney. Editor Mac Wade (George Bancroft) sends out reporters and promises Babe Bennett (Jean Arthur) a paid vacation for a good story. The opera board elects Deeds chairman and expects him to pay their $180,000 deficit; but he says no. The lawyer Hallor (Charles Lane) asks Deeds for a million for his uncle's common law wife; but Deeds says it's fishy. Deeds tells Cedar he wants to see the books. Deeds puts on a new suit, locks up his two bodyguards, and goes out in the rain. Babe falls down, and he takes her to dinner. They join a table of writers; but Deeds objects to their laughing at him and punches two of them.
The editor likes Babe's story on the Cinderella man. His valet Walter (Raymond Walburn) wakes up Deeds and says he came home in his shorts drunk. Cobb (Lionel Stander) shows Deeds the newspaper and advises against punching the editor in the nose. Babe, calling herself Mary Dawson, shows Deeds around town. He admires the America of Grant and quotes Thoreau. He jumps on a fire truck to help. Babe tells Mabel Dawson (Ruth Donnelly) about Deeds' goodness and packs to leave. Deeds comes in, and they go out walking. Deeds says he's going home. He hopes to replace his imaginary girl with someone real, and he gives her a love poem. She embraces him, and he runs off. Babe tells her editor that Deeds proposed, and she cries. Cobb proves to Deeds that Babe is a reporter. Deeds calls her, and she admits she wrote the articles. Deeds tells Walter to pack his things. A farmer criticizes Deeds for not helping the poor; he pulls a gun, drops it, and cries. Deeds gives him dinner. Then he plans to give his money away in small farms, taking applicants at home. Deeds orders lunch for 2,000 men. Cedar gets a relative to sign a document, and Deeds is arrested as insane.
Babe tries to see Deeds but can't. Cobb wants to get him a lawyer, but Deeds says nothing. In court the judge learns Deeds has no counsel and no defense. Cedar says Deeds violently attacked those examining him. Babe says Deeds is not insane and tries to defend him. Two sisters testify that Deeds is pixilated. A doctor testifies that Deeds is manic depressive, wanting to help humanity when he is elated. The judges commit Deeds, but Babe pleads for him to speak and explains how she hurt him, saying he is honest and admitting she is in love with him. Deeds explains his tuba playing is like others who doodle or fidget. He admits he got drunk once and shows that the two sisters think everyone is pixilated. He wants to help those who need it instead of those, like Cedar, who don't. Then he slugs Cedar. The judges declare Deeds sane, and the cheering crowd carries him out. Babe stays behind in court crying. Deeds runs back and takes her in his arms, kissing her.
This Frank Capra film contrasts simple wisdom with city slickers, turning capitalist society on its head by suggesting that the rich could use their wealth to give the poor needed opportunity. Deeds' main flaw seems to be his habit of punching obnoxious people in the face.