"Citizen Kane" is loosely based on the life of "yellow journalism" newspaper magnate William Randolph Hearst. Kane (Orson Welles, who also directed and co-wrote the screenplay) is separated from his parents as a child and made heir to an enormous fortune. Coming of age, he decides to run a newspaper, sensationalizing the news and considering himself to be the voice of the people. He develops loyal colleagues in Jedediah Leland (Joseph Cotten) and Bernstein (Everett Sloane). With ambitions beyond publishing, he runs for New York Governor, and later promotes the singing career of second wife Susan (Dorothy Comingore). He also builds Xanadu, an extravagant palace that is never finished. These various ambitions fail, and Kane dies a wealthy but spiritually broken man.

"Citizen Kane" is a character study, about a man who superficially has everything, but still isn't satisfied. Charles Foster Kane has to prove something, but that something always changes, and simply cannot be achieved. This is demonstrated at length by Kane building a lavish opera house for Susan to perform in, then sending her on a cross-country tour, in the face of widespread ridicule of her hopeless lack of talent.

The film is at its best when Kane is a young man, dynamic and with the straightforward goal of "defending the working man". A scene where he sings and dances with chorus girls is marvelous chaos. Also outstanding is a series of breakfast encounters between Kane and first wife Emily (Ruth Warrick) that cover several years and show the fading of the marriage. In comparison, later scenes drag ever so slightly, as Kane is reduced to playing lord of Xanadu.

"Citizen Kane" plays little tricks with the audience. Early in the film, there is a perfect send-up of the newsreels. In the scene that Kane's parents discuss his future, he can be seen through a window playing in the snow. The chronology mixes past and present events, with dialogue in the present giving away subsequent events that take place in the past.

Welles was the leader of the Mercury players, and "Citizen Kane" marked their transition from radio to cinema. Welles, Cotten, and Moorehead would also appear together in "Journey Into Fear" and "The Magnificent Ambersons" before nervous studio executives put a halt to Welles' projects.