It's New York in the 1940s and Joseph Mitchell (STANLEY TUCCI) has a good life. He's happily married to Therese (HOPE DAVIS), a photographer with whom he has two young daughters, and his career as a writer for the New York Times is going rather well.
Joe Gould (IAN HOLM), on the other hand, is a small, disheveled and somewhat crazy looking, homeless man who lives on the street and gets by with the help and contributions of his many acquaintances throughout the city, including painter Alice Neel (SUSAN SARANDON) and gallery owner Vivian Marquie (PATRICIA CLARKSON). A self-proclaimed scholar of the streets, Gould is best described as a bohemian whose literary masterpiece, "The Oral History of Our Time" - an essay and collection of overheard conversations and remarks from everyday city folk - exists mainly in his head.
When Mitchell first witnesses Gould, he's fascinated by this walking contradiction and becomes acquainted with him, obviously seeing him as the source for a new writing piece. Mitchell eventually publishes his story that not only brings momentary fame to Gould along with the attention of big publisher Charlie Duell (STEVE MARTIN), but also so instantly bonds Gould to Mitchell that the writer soon finds that he can't get rid of his company.