Mr. Gregory Grumm is the Principal of the School Mayzie McGrew attends. His offices if full of books that he likes to read. He is seen reading a a few books with a looking machine as the The Cat in the Hat in his office introduces him to the viewers.
When Miss Sneetcher informs what has happened to Mayzie, Mr Grumm studies the daisy on Mayzie head but when he notices the daisy going dead its costing Mayzie her life as well as he also notices her feeling dehydrated. he Quickly orders Miss Sneetcher to get her some water. She obeys and grabs a vase of flowers that has water in it and splashes it onto Mayzie's head as she and the daisy are feeling well and hydrated again.
He is voiced by Lewis Arquette.