As is common in Hawthorne's short stories, "My Kinsman, Major Molineux" focuses primarily on a single character, with almost every other figure serving to emphasize the protagonist's traits. Robin's self-perception contrasts sharply with how the reader sees him. The young man is hopeful and considers himself "shrewd" (a term used ironically throughout the narrative). He believes he will achieve success with the aid of his well-connected uncle. Consequently, he fails to notice the numerous clues from the townspeople that his uncle is not who he thinks he is, and he does not realize he is being mocked by the locals.

Without a doubt, Robin is naive. Whether he is to blame for this naivety is debatable. Some argue that the story illustrates how youthful ideals can be quickly destroyed; from this perspective, Robin's swift shift from admirer to persecutor shows how easily adolescents can be influenced by mob mentality, especially when he witnesses his uncle being chased out of town by an angry mob. However, one could argue that Robin's status as a newcomer among potentially hostile people might justify his actions. Although it may be challenging to find concrete evidence in the story to support this interpretation, there are indications that by the time Robin sees the crowd, he is sufficiently scared to do whatever he feels is necessary to protect himself—an action reminiscent of St. Peter among the crowds witnessing Christ's sentencing to crucifixion.

Gentleman
The final individual Robin encounters during his night of confusion and diversions is a gentleman with an "open, cheerful, and altogether prepossessing" appearance. He is the only person in the city who speaks kindly to Robin. Intrigued by how Robin will respond to seeing his disgraced relative, he sits with Robin on the church steps and engages him in conversation while they wait.

Major Molineux
Very little is known about Major Molineux, the relative Robin is searching for. He does not utter a single word in the narrative, and inquiries about him are met with silence. As Robin's father's first cousin, Molineux is a wealthy man without children who has shown an interest in helping Robin start a career. He holds the rank of major in the British military, serving in what remains a British colony. Although he is tarred and feathered by the story's conclusion, there is no indication of his wrongdoing. Even in disgrace, the narrator describes Molineux as "an elderly man, of large and majestic person, and strong, square features, betokening a steady soul."

Robin Molineux
Robin, the protagonist of the story, is a nearly eighteen-year-old who has traveled from the countryside to locate his relative, Major Molineux. Robin is the son of a country minister who also runs a small farm. Since his older brother is set to inherit the farm, Robin hopes that Major Molineux can help him secure another profession. This is Robin's first visit to the city, and his appearance, manner of speaking, and the club he carries all mark him as a country boy out of his depth. Back home, Robin is seen as a "shrewd youth," but in the city, he misinterprets everything he observes. He repeatedly asks for assistance in finding his relative, only to be met with indifference or hostility. Each time, he assumes their refusal to help is due to their ignorance, rudeness, or low status. It isn't until he sees his relative tarred and feathered that Robin comprehends the people's animosity towards Molineux. Realizing his profound naivety, Robin concludes that returning home might be his wisest option.