Main Characters:
* John "Johnnie" Chapman: The protagonist, a troubled teenager dealing with the loss of his father and struggles at school. He is initially skeptical of the Pig Man but becomes fascinated by the mystery surrounding him.
* Mr. Pignati: The "Pig Man" himself, a lonely, elderly man who befriends Johnnie and Lorraine. He is eccentric and kind-hearted, with a love for animals.
* Lorraine Jensen: Johnnie's classmate and friend. She is a compassionate and resourceful girl who is also dealing with personal challenges.
Supporting Characters:
* Norton: Johnnie's best friend, who initially doesn't believe in the Pig Man.
* Mr. and Mrs. Chapman: Johnnie's parents, who are grieving the loss of their son.
* Mr. and Mrs. Jensen: Lorraine's parents, who are supportive but sometimes distant.
* Mr. and Mrs. Conigliaro: Neighbors who are suspicious of the Pig Man.
* The Principal: The headmaster of Johnnie's school, who is strict and unsympathetic.
* The Teacher: Johnnie's English teacher, who encourages his writing.
* The Gang: A group of bullies who torment Johnnie and Lorraine.
* The Animals: The various animals that Mr. Pignati cares for, including the pigeons, rabbits, and the pig.
Note: This list does not include all the characters in the book, but focuses on the most important ones.