John Harmon is a fictional character from Charles Dickens' novel, "Our Mutual Friend." He is the son of a wealthy man who leaves him a fortune, but he is initially thought to be dead. His return to London sets off a series of events that explore themes of wealth, love, and social class. Throughout the story, John Harmon struggles with his identity and the expectations placed upon him. He is deeply connected to other characters, including Bella Wilfer, whom he loves, and Mr. Boffin, who becomes his guardian. Harmon's journey reflects the complexities of human relationships and the impact of money on personal values.