She is portrayed by Anjelica Huston, who also plays Miss Battle-Axe in the film adaptation and portrayed Miss Harridan in the 2003 film Daddy Day Care.
As one of the most influential and powerful sorceresses on Earth, she leads a secret society of like-minded witches in their never-ending quest to kill and torture children.
In the past, the Grand High Witch faced off against Helga Evesheim (Luke's grandmother) during the latter's quest to find out more about witches, and even considered her an "old adversary" upon their chance meeting at the hotel in England.
During each and every single meeting she ever attended, she would murder one of her own followers simply to keep the other witches focused. This was considered to be her ultimate punishment, and the other witches were terrified of her.
The Grand High Witch especially had a plan that would climax in turning all the children of England into mice, to be disposed of either by the witches themselves, or by their unsuspecting parents. She demonstrates her formula by inviting a boy called Bruno, who had been previously given a chocolate with the formula, as he slowly turns into a mouse. However, the meeting was being eavesdropped by Luke, a boy who was in the hotel with his grandmother Helga, who warned him about witches and is implied to have faced the Grand High Witch before.
One of the witches catches the scent of Luke, so the Grand High Witch tracks him down and force-feeds him her formula, turning him into a mouse as well. He manages to escape and meet with Bruno, the two going after Helga's room, where they plan to stop the witches plan. Luke manages to steal the formula and slip it on the witches soup. In the end, the Grand High Witch suffered a somewhat fitting demise when her own magic was used against her and she (along with all of her followers, except Susan Irvine whom she banned in the celebration) is transformed into a mouse. While the mice-transformed witches run rampant around the hotel and are killed by the staff, the Grand High Witch is killed by the hotel manager, who uses a cleaver to slice her in half.
The Grand High Witch is extremely disturbing for a villain appearing in a book for children, and is scarier than most villains appearing in stories for adults. Bluntly put, she is a child-murderer and a genocidal psychopath.
One of here favorite ways to depose of children was to turn them into animals their parents hated, and have the parents kill their own children, thinking they where pests. Her contempt also expands to any witch who dares question her, and all other witches live in total fear and submission of her. Her meetings usually involve her killing any disobedient witch, and she possibly deliberately kills a witch yearly, to keep the others on their toes. She also cares little for human adults, and doesn't mind if she accidentally kills them. Being a witch, she is a separate species to humans, and is motivated to hate kids as her well-developed nose makes them smell like dog feces to her.
- According to Luke's Grandmother, the Grand High Witch is "the most evil woman in creation". Unlike the other witches, she wishes to kill all the children in England.
- It should be noted that while in the book, the Grand High Witch is the first witch to transform into a mouse, in the movie she is the last (unless you count Susan Irvine, who didn't transform at all).
- Unlike the other witches, who at least show a little concern for adults, she has no results for collateral damage in her schemes. This is shown when a witch asks what would happen if an adult consumed their formula, and the Grand High Witch replies, "Then that's just too bad for the grownup".
- In the book, the Grand High Witch doesn't take off her gloves, wig or shoes which implies she has more to hide, while she does do so in the film.
- In the book, it is revealed that the Grand High Witch is Norwegian, and she is also a famous baroness in Norway.
- In a Google Hangout, Lucy Dahl revealed that the Grand High Witch was in part based on her stepmother. Lucy stated it wasn't her stepmother's personality, but the look and social status that was the inspiring factor.
- Lucy also seriously stated she wasn't entirely convinced witches were fiction, citing a neighbor who, "If Witches are real, she's one of them."
- The Grand High Witch has countless subordinates, including The Woman in Black and Lois Leffour.
- Roald Dahl hated the film due to the changed ending, but he loved Angelica Huston's performance.