Gregory’s mother is a cook in a restaurant. She is a caring mother who tries to take the time to listen to Gregory and help him process his feelings, but she often does not give Gregory the kind of attention he wants. The text implies that she is under financial pressure. Gregory’s father has become a security guard after losing a prior job as a factory worker. He is not as present in the story as is Gregory’s mother, but he does support Gregory’s desire to be outside when Gregory’s mother tries to get him to stay home, showing that he is sympathetic to his son’s needs even if he is not well-positioned to offer Gregory any real attention.

Gregory’s parents’ inability to give him significant attention shows in several ways. Under pressure to move house quickly, Gregory’s parents cannot arrange for him to have a birthday celebration. When Mother asks Gregory about his feelings regarding Uncle Max and his new school, she offers him platitudes about everything eventually turning out okay rather than useful strategies for dealing with his classmates. Both of his parents are too busy to come out and see Gregory’s drawings in the chalk factory. 

However, at the end of the story, both Mother and Daddy make sure to tell Gregory that they are proud of his accomplishments in the chalk garden. They want to do what is right for Gregory, but sometimes the pressure of their current circumstances gets in their way.

Gregory’s uncle is 20 years old, has a red beard, and plays the guitar. When the story opens, he is out of work and needs a place to live, so he moves in with Gregory and his parents. Gregory does not particularly like Max, who “thinks no one is important but him” (16) and can never hold a job for very long. The story supports Gregory’s opinion about Max’s selfishness and poor work ethic by showing that all Max does all day is watch television, sleep, and play his guitar.

Max is insensitive to Gregory’s feelings, repeatedly teasing Gregory by calling him “The Paintbrush Kid” (15) and “The Chalk Box Kid” (57). He covers up Gregory’s art in their shared bedroom with his car posters and then, when Gregory protests, tells Gregory it is “too bad” (20) instead of apologizing. His characterization as a mild bully makes him a temporary antagonist for Gregory. However, Max is a dynamic character who changes somewhat by the end of the story. After he sees Gregory’s garden, he is more respectful toward Gregory and even takes down his car posters so that Gregory’s art can be seen again.

The three significant adult characters that Gregory meets through his new school are Miss Perry, Miss Cartwright, and Mr. Hiller. Miss Perry is Gregory’s teacher in Room 3 at Dover Street School. Gregory thinks that she is nice, and the way that she pays her students individual attention and is supportive of their individual interests backs up his assessment. She talks to Gregory about his garden and, along with Miss Cartwright, is behind the special celebration of Ivy winning the school’s art competition. Miss Cartwright is involved with Ivy’s party because she is the school’s art teacher. Gregory has class with her just a few hours a week, so she is not as frequently mentioned in the story. Mr. Hiller—a friend of Miss Perry’s who comes to school to talk about his plant nursery and distribute cuttings to the children—also makes just a few appearances in the story.

These three adults are flat and static characters whose main function is to help drive the plot toward the resolution of its central conflict. Miss Perry, Miss Cartwright, and Mr. Hiller play important roles in Greogry’s adjustment to his new home and school. Miss Perry invites Mr. Hiller to the school, and Mr. Hiller draws plants on the chalkboard, getting Gregory excited about the idea of a garden he can draw. After Miss Perry learns the true nature of Gregory’s garden, she arranges for herself, Miss Cartwright, and Mr. Hiller to visit. The three adults communicate their admiration of the garden to Gregory and make a public fuss over him; Mr. Hiller is the one who ensures that Gregory’s parents understand what a special thing their son has done. The actions of Miss Perry, Miss Cartwright, and Mr. Hiller are key to Gregory’s creation of his garden and its eventual role in helping him be seen by his parents and develop friendships at school.

Vance, a student in Gregory’s class, is the ringleader of a group of boys who challenge and exclude Gregory. Vance takes offense easily, initially targeting Gregory simply because Gregory remarks that his old school is bigger than the Dover Street School. Vance accuses Gregory of bragging, indicating that he feels insecure at the idea that the school he attends might not be the best and that he wants other people to have a humble attitude when they compare themselves with him.

For most of the story, Vance functions as an antagonist to Gregory. He discourages other students from getting to know Gregory and becoming Gregory’s friends. Vance is also the one who brings the other students to Gregory’s home to mock the chalk garden, going so far as to announce that “[i]t’s nothing. It’s nothing at all” (49). However, Vance is a dynamic character who, after seeing the respect that his teachers and Ivy have for Gregory’s art, changes his attitude toward both the art and Gregory himself. At the end of the story, he has started to be friendly to Gregory at school, even showing empathy and kindness by going out of his way to mention the photo of Gregory’s garden hanging in Mr. Hiller’s nursery and suggesting that Gregory might want to go see it.