Charles Wallace has blue eyes, and is repeatedly described as small for his age. At five, Charles Wallace has an IQ and a vocabulary of a college student. This is offset somewhat by a mature and serious demeanor.
Of the Murray children, Charles Wallace stands out as being the most extraordinary. In the first book, it is mentioned that Charles Wallace did not learn to talk until he was almost four but afterwards began talking in full sentences, skipping over the "baby preliminaries.” He always speaks in a very formal manner with no slang or abbreviations much as an adult professor would. Charles possesses an almost unfathomable amount of intellect and knowledge for his age. At the beginning of Charles’ character development, this immense intelligence makes Charles in danger of falling into complacency and arrogance about his abilities.
Charles Wallace is also characterized by a sense that he is in some way, alien and not fully human. Although none of the novels explicitly say that Charles Wallace is anything but human, there are many hints throughout that Charles possesses senses and knowledge that are not of this world. He is telepathic and able to pick up on what those closest to him are thinking and feeling especially Mrs. Murray and Meg. He often senses or knows about things which are about to happen before the other characters. Charles also has a much more open mind than his older siblings and friends. Although he does not believe in the childish fantasies of most young children, he is the most open to the impossible and fantastic such as when the cherubim Progo appears in the "Wind in the Door."
Because of his extreme intelligence and other-worldly nature, he is often bullied by other children and misunderstood by adults outside his family. He is often beaten up by older children at school and ridiculed by adults in town.
Charles Wallace prefers to be called Charles Wallace rather than Charlie or Chuck, as noted in Wind and Planet, but Meg frequently calls him simply Charles. In A Swiftly Tilting Planet, he allows Mrs. O'Keefe to call him Chuck, correctly guessing that she is identifying him with someone from her personal past (her brother, as it turns out).
According to an April 2004 article in The New Yorker, Charles Wallace is thought to be partly based on Madeleine L'Engle's son, the late Bion Franklin. L'Engle herself has acknowledged that Bion was the model for another of her characters, Rob Austin, but has not stated a similar provenance for Charles Wallace.
In A Wrinkle in Time, Charles Wallace befriends the mysterious Mrs Whatsit, Mrs Who and Mrs Which, who send him, along with his sister Meg and Calvin O'Keefe, to rescue his father from the planet Camazotz. Trusting too much in his own abilities, Charles Wallace allows himself to join with the mind of IT, pure evil incarnated as a disembodied brain, and must himself be rescued by Meg.
In A Wind in the Door, Charles Wallace is bullied by fellow children and attacked by supernatural characters called the Echthroi, the forces of evil and "Xing." They cause Charles Wallace's mitochondria to sicken by interfering with the fictional "farandolae" within them. An intergalactic group including a snake, a cherubim, a grade school principal, and Meg influence, encourage the young farandolae to "deepen," thus saving Charles Wallace's life.
In A Swiftly Tilting Planet, fifteen-year-old Charles Wallace travels in time to try to stop Mad Dog Branzillo's nuclear plans, going "within" various characters whose actions will help determine Branzillo's ancestry, and whether he is a mad dictator or "a man of peace." Again the Echthroi attack Charles Wallace and try to prevent him from completing his mission.
Meg and Calvin's second eldest child, Charles O'Keefe, is named after Charles Wallace, his uncle. Charles O'Keefe is introduced in The Arm of the Starfish (1965) and also appears in Dragons in the Waters (1976). Like Charles Wallace, Charles O'Keefe is depicted as being empathic, especially with respect to the people he loves. Ironically, however, Charles Wallace Murry is mysteriously absent from the books in which Charles O'Keefe and his elder sister Polly (sometimes spelled Poly, short for Polyhymnia) appear. In A House Like a Lotus (1984), Polly writes that "Mother's youngest brother, the one Charles is named after, is off somewhere on some kind of secret mission, we don't know where." Later, in An Acceptable Time (1989), Polly is given Charles Wallace's old room, newly redecorated for her, when she stays at her grandparents' house.
Charles Wallace is named after Madeleine L'Engle's father, Charles Wadworth Camp, and her husband Hugh Franklin's father, Wallace Collin Franklin. The novel A Wrinkle in Time, the plot of which centers on Charles Wallace and Meg trying to retrieve their absent father, is dedicated to both men. (Camp died in 1935, when L'Engle was a teenager.) L'Engle also used the name Wallace for Dr. Wallace "Wally" Austin, the father of Vicky Austin and her three siblings in the Austin family series of books.
In 2003, David Dorfman portrayed Charles Wallace Murry in the Disney television adaptation of A Wrinkle in Time. It was broadcast on ABC, directed by John Kent Harrison, from an adapted teleplay by Susan Shilliday.