As the tale begins, it is Sherlock Holmes' love of mental puzzles that leads to his interest in the odd story Jabez Wilson tells him. His knowledge of crime and ability to reason allow him to discern that a serious motive must lie behind Wilson's singular experience with the bizarre Red-Headed League. Guided by this knowledge, and the observations he makes as a result, he stops a bank robbery and the further lawless career of a master criminal. Through Jabez Wilson, whom Holmes disdains as "not over-bright," we learn that ignorance—especially when it is accompanied by greed— can make people unwitting accomplices to crime.

Sherlock Holmes, by contrast, personifies the virtue of unselfishness. After foiling the attempted bank robbery, he tells the manager Mr. Merryweather that he expects no reward beyond the repayment of his expenses. In addition, by helping good to triumph over evil, Sherlock Holmes eliminates the threat to his community's stability. Even though Holmes works with the police, and his investigation serves the interests of law and justice, this is not his greatest concern.

In fact, Holmes does not appear to recognize that he has accomplished a humanitarian act until Watson reminds him that he is "a benefactor of the race." Instead, the most important type of order restored when the mystery is solved is an economic order. The belief that money received should be directly proportionate to the amount of work accomplished is jeopardized during the course of the story. Not only do the bank robbers desire money they have not earned, but Jabez Wilson twice attempts to get something for nothing: the labor of John Clay as his assistant and payment from the Red- Headed League based solely on the color of Wilson's hair and ability to copy from the dictionary. Sherlock Holmes correctly perceives that his strongest clue rests in this imbalance between work and payment, and at the story's end, balance is restored.

The two characters of greatest interest to readers in this story are Sherlock Holmes and Dr. Watson. Holmes possesses a nearly superhuman ability to read a person's background by observing small, seemingly insignificant details, and Watson states that Holmes' powers of reasoning make him appear to be "a man whose knowledge was not that of other mortals." He is aided in his task by a thorough familiarity with previous criminal cases and the inhabitants of London's underworld, along with a scholarly knowledge of such obscure topics as varieties of cigarette ash and kinds of tattoo marks. Possessing a sort of split personality, Holmes swings between moods of thoughtful inactivity and intense action. Even though he is happy to help the police catch criminals when a case interests him, Holmes is more concerned with the pleasure he derives from these mental games. As he tells Watson, "My life is spent in one long effort to escape from the commonplaces of existence. These little problems help me to do so."

Dr. Watson is Holmes’s closest friend, who often accompanies him in his investigations and records the most interesting ones, which Holmes accuses Watson of embellishing. Watson is loyal, courageous, and deeply attached to Holmes. Although he practices as a physician, he seems to spend most of his time assisting his friend. In “The Red-Headed League,” when Holmes asks Watson to accompany him into a dark cellar late at night, armed with a revolver, Watson agrees to do so without question. Despite his intelligence, Watson’s mind does not function on the same level as Holmes’s, and he often feels frustrated that, having seen and heard the same clues as Holmes, he has not been able to draw any conclusions from them. In this way, Watson can be seen as a stand-in for the reader, who also sees the clues yet (in most instances) cannot deduce the solution.

As the tale begins, it is Sherlock Holmes' love of mental puzzles that leads to his interest in the odd story Jabez Wilson tells him. His knowledge of crime and ability to reason allow him to discern that a serious motive must lie behind Wilson's singular experience with the bizarre Red-Headed League. Guided by this knowledge, and the observations he makes as a result, he stops a bank robbery and the further lawless career of a master criminal. Through Jabez Wilson, whom Holmes disdains as "not over-bright," we learn that ignorance—especially when it is accompanied by greed— can make people unwitting accomplices to crime.

The bank robber John Clay and his accomplice Archie are motivated by the fabulous sum of money they hope to steal from the City and Suburban Bank. Their greed takes them outside the bounds of law and leads to their capture. Even though the story ends before their trial and punishment, the likely penalty for their history of criminal acts would be execution, demonstrating the fatal consequences of greed. Jabez Wilson's love of money also promotes crime and makes him an easy target for exploitation. Not only does the promise of money in return for very little work take him away from his shop so John Clay will have free rein, he first becomes vulnerable when he hires Clay as his assistant, thinking he is getting the better bargain because Clay was "willing to come for half wages so as to learn the business."

Throughout the story, we are confronted with a series of situations that are not what they first seem. Jabez Wilson simply wishes to learn what has happened to the Red- Headed League and his weekly payment of four pounds, unaware that this odd mystery is a smokescreen for bank robbery. Watson contrasts the "uncongenial atmosphere" surrounding Jabez Wilson's pawnshop with the "fine shops and stately business premises" that adjoin the City and Suburban Bank, but the two locales are connected by an underground tunnel. The criminals themselves do not even appear criminal. Watson describes John Clay, a thief and murderer, as "a bright-looking, clean-shaven young fellow" when he first sees Clay at the pawnshop door, later noting his "white, almost womanly hand" and "clean-cut, boyish face" at the moment of Clay's capture. Little can be taken at face value in "The Red-Headed League." Because both Wilson and Watson so readily believe that outward appearances reveal truth, we are reminded that this is a common human failing. It is even sometimes appropriate, as we learn when Jabez Wilson turns out to be exactly the kind of man that both Watson and Holmes guessed him to be. But it is also the detective's job to be suspicious of appearances and suspend judgment until all the evidence has been unearthed.

A keen intellect is not always a force for good, however. Only a brilliant mind like John Clay's could pinpoint Wilson as the ideal target and conceive of the Red-Headed League as the perfect scheme to divert Wilson's attention from his business while a tunnel is being dug in his cellar. This is where the motives and morality guiding the actions of an intelligent mind become important, and where the key differences between the detective and criminal emerge.

The bank robber John Clay and his accomplice Archie are motivated by the fabulous sum of money they hope to steal from the City and Suburban Bank. Their greed takes them outside the bounds of law and leads to their capture. Even though the story ends before their trial and punishment, the likely penalty for their history of criminal acts would be execution, demonstrating the fatal consequences of greed. Jabez Wilson's love of money also promotes crime and makes him an easy target for exploitation. Not only does the promise of money in return for very little work take him away from his shop so John Clay will have free rein, he first becomes vulnerable when he hires Clay as his assistant, thinking he is getting the better bargain because Clay was "willing to come for half wages so as to learn the business."

Throughout the story, we are confronted with a series of situations that are not what they first seem. Jabez Wilson simply wishes to learn what has happened to the Red- Headed League and his weekly payment of four pounds, unaware that this odd mystery is a smokescreen for bank robbery. Watson contrasts the "uncongenial atmosphere" surrounding Jabez Wilson's pawnshop with the "fine shops and stately business premises" that adjoin the City and Suburban Bank, but the two locales are connected by an underground tunnel. The criminals themselves do not even appear criminal. Watson describes John Clay, a thief and murderer, as "a bright-looking, clean-shaven young fellow" when he first sees Clay at the pawnshop door, later noting his "white, almost womanly hand" and "clean-cut, boyish face" at the moment of Clay's capture. Little can be taken at face value in "The Red-Headed League." Because both Wilson and Watson so readily believe that outward appearances reveal truth, we are reminded that this is a common human failing. It is even sometimes appropriate, as we learn when Jabez Wilson turns out to be exactly the kind of man that both Watson and Holmes guessed him to be. But it is also the detective's job to be suspicious of appearances and suspend judgment until all the evidence has been unearthed.

Duncan Ross is a young red-haired man who poses as an official of the Red-Headed League and interviews Jabez Wilson for his position. He uses the alias “Willian Morris,” and the name “Duncan Ross” is likely to be an alias as well. Ross/Morris is John Clay’s accomplice in the bank robbery, and he escapes from the cellar, though he is apprehended by the police at the door. He displays a sense of humor when he pulls Wilson’s hair and describes the lengths to which previous applicants have gone in their attempts to join the league.

Peter Jones is a police detective from Scotland Yard. Holmes describes him as brave and tenacious but very stupid, and Jones himself admits that he has been pursuing John Clay for years without any success. However, Jones is patronizing in his manner, saying that Holmes “has the makings of a detective in him” but that his methods are “just a little too theoretical and fantastic.” He is one of the more extreme examples of the unimaginative, officious Scotland Yard detective to appear in Conan Doyle’s stories.

Mr Merryweather is a director of the City and Suburban Bank. He is thin, respectable-looking, and gloomy, making his name somewhat ironic. Merryweather is skeptical about the robbery and is mainly concerned that the adventure will cause him to miss his customary game of Bridge for the first Saturday night in twenty-seven years.

See Duncan Ross.