Jay Gatsby is the enigmatic protagonist of F. Scott Fitzgerald's novel 'The Great Gatsby', representing the American Dream and its disillusionment. Gatsby is a wealthy and mysterious figure known for his extravagant parties and obsessive love for Daisy Buchanan, which ultimately drives much of the novel's plot. His characterization highlights themes of aspiration, identity, and the social divide in 1920s America, shaped by the perspectives of other characters.