Charlie was born with pyrokinetic powers. A secret government agency called The Shop wanted to capture Charlie for weapons research.
Charlene Roberta "Charlie" McGee was born to Andrew "Andy" McGee and Victoria "Vicky" Tomlinson with her abilities due to her parents having participated in a mysterious government-funded experiment during college. Both parents had been injected with unknown amounts of a drug known as Lot Six, which, among other things, had been proven to alter the subject's chromosomes and pituitary gland.
Charlie was born with pyrokinesis, but she also had powers that she inherited from her parents: mental domination, telepathy, telekinesis, and precognition. All of her powers were connected with her power to start fires. She sometimes had a hard time controlling her abilities, especially when she was upset or angry. Also, as she got older it did seem like her powers were growing and she was also getting better control. It is later stated that, when Charlie grows older, she may be able to cause nuclear explosions by sheer force of will, with some of the doctors responsible for the experiment believing that one day she may be powerful enough to crack the whole planet in two. While her precise limits are unclear, she was sufficiently powerful to overload the power-sucking Cody to the point that he was killed from the strain of trying to absorb her power. Unlike her parents, Charlie does not receive any strain from using her abilities.
In the book, Charlie is described as having blond hair and blue eyes. She is very beautiful, looks like her mother, and is also tall for her age. She is also very stubborn, intelligent, and strong. At first she didn't want to hurt anybody, but, after her father's death and all the events surrounding the movie, she decides that she will use her power on people, if they are a threat.
In the film "Firestarter", Charlie was portrayed by actress Drew Barrymore. In the miniseries "Firestarter: Rekindled", she was portrayed by Skye McCole Bartusiak and Marguerite Moreau played the 20 year old Charlie.