Enzo
Enzo is the narrator of The Art of Racing in the Rain and a loyal, loving, and intelligent dog. He philosophizes about reincarnation and the meaning of life. He is convinced he has the soul of a human and desires to one day be reincarnated as one. The development of his near-human sophisticated thought process began the day his owner Denny left the television on, and since that day he has watched educational programs to expand his knowledge while Denny works. His frustration about his body and its limitations grows with his increasing intelligence, and he expresses feelings of being trapped in his dog body. Enzo complains about his lack of thumbs and subpar eyesight throughout the story, explaining how dogs would be far more useful if they had functioning thumbs. His frustrations with his dog form and some human logic provide a sense of light humor throughout the novel.
Denny
Enzo’s owner and best friend. He works as a customer service technician at an auto-body shop specializing in high-end vehicles, but his true passion lies in racecar driving. He specializes, as suggested by the novel's title, in racing in the rain. Despite his devotion to being a husband and father, his in-laws look down on him for his blue-collar background and passion for racing. Over the course of the novel, Denny transforms from a young bachelor to a responsible family man, but he never loses sight of his bond with Enzo, who was with him through it all.
Eve
Denny’s girlfriend, who eventually becomes his wife and the mother of his daughter, Zoë. Eve is not welcomed by Enzo right away, but once she becomes pregnant with Zoë, she earns his trust and acceptance. She falls ill in the middle of the story, and although Enzo senses her terminal illness, Eve is unaware of her condition and becomes an unhappy, short-tempered, and anxious person. This change in personality causes a strain on not only her marriage with Denny, but all other personal relationships in her life as well, including the one with her own daughter. As she finally accepts her diagnosis and fate, she finds peace and again becomes the person she was in the beginning of the story.
Zoë
Denny and Eve’s daughter. The novel tracks Zoë's childhood from being a newborn to a grade-schooler with wisdom far beyond her years. She shares a lot of her father's tenacity and intuition, eventually proving herself to be a capable racecar driver on the go-kart track. When her grandparents try to steal her away from her father, she never stops believing in Denny's ability to get her back. When she is older, Zoë is the one who introduces human Enzo to Denny when they are living in Italy.
Maxwell & Trish
Eve’s parents, also called “The Twins” by Enzo due to their similarity in clothing and snobbishness, and later as "The Evil Twins" after they conspire to have Denny accused of rape in order to steal custody of Zoë. They disapprove of Eve’s marriage to Denny and sue him for custody of Zoë after Eve’s death. Their disapproval stems from Denny's blue-collar background.
Annika
A 15-year-old girl and distant relative of Eve who has a crush on Denny and forces herself on him while he sleeps. She later accuses Denny of rape and causes him to be arrested and almost lose custody of his daughter. After being confronted by Denny years later, Annika has a change of heart and recants her accusation in court.
Mike
Denny’s friend and co-worker. Mike provides support and friendship during Denny’s difficult times through the custody battle and criminal charges.
Tony
Mike’s partner.
Craig
Owner of the garage where Denny works.
Mark Fein
Denny’s first lawyer who he hires for the custody battle over Zoë. Mark oozes charisma and confidence. Denny knows him from the auto-body shop, where he is a client. He does a good job defending Denny, but he has to be replaced after he lands a job as a circuit court judge.
Mr. Lawrence
Denny’s replacement lawyer. He doesn’t have as much enthusiasm and vigor as Mark, but ends up helping Denny win custody of Zoe.
Luca Pantoni
A representative of the car company Ferrari. He offers Denny a job as a test driver in Italy towards the end of the novel. Luca takes a special interest in Denny because he, too, lost his wife many years ago, and his grief was so serious that he almost died; but he was saved by a mentor who believed in him. Luca knows how talented Denny is, but he is especially impressed by his emotional courage.
