The Cat In The Hat - The essence of mischief, fun and imagination. The Cat stirs things up, causes trouble, but always sets things right again, helping Jojo to discover the power of imagination as they create the story for the show together. Look for a physically adept actor (male or female) to play the Cat, one who will be able to play many comic cameos (Dr. Dake, helicopter reporter, TV interviewer, auctioneer, Mr. McGurkus, etc.) and is comfortable improvising with an audience.
Jojo/the Boy - Jojo is a "Thinker"--a smart child with a wild imagination. He can be played as being a little bit awkward, a little bit of a loner, or simply a rambunctious kid whose 'Thinks' get him into constant trouble. By the end of the show, he learns what it means to be a responsible member of his world, using the power and possibilities of his own 'Thinks.'
Horton The Elephant - Gentle, rotund and appealing. Think of him as a big-hearted blue collar guy who is steadfast and responsible and always tries to do the right thing for his friends. He is imaginative and receptive to the world around him. He is very un-self-conscious. Horton's view of the world never changes--he believes in its goodness. But by the end of the show, without even realizing it, he is ready to become a parent.
Gertrude Mcfuzz - Very self-conscious and aware that her one-feather tail isn't perfect. Gertrude changes during the show from a vain, neurotic, nervous and shy bird into one with the power to protect and care for a baby elephant bird and commit herself to Horton. In other words, she stops worrying about her looks and grows up doing what she wants.
Mayzie Labird - Self-centered, selfish and vain, Mayzie will never admit to her own flaws. She manipulates anyone she can (especially Horton) into doing what she wants. But Mayzie isn't all bad. In giving up her egg to Horton once and for all, she has a moment of generosity--she realizes she isn't the kind of person who'd be a good parent, and she does the best thing she can do for the egg.
Sour Kangaroo - She isn't really sour at all. She's just got a lot of attitude. She's loud, brassy and a lot of fun.
Young Kangaroo - the child of Sour Kangaroo. Just as sassy, just smaller!
The Wickershams - These are not bad guys! They're simply a lot like kids who tease, play pranks and get a kick out of making mischief, although often at others' expense. They enjoy hanging around with one another, making music together on the street corner, and playing off one another.
The Whos - They're a lot like you and me only so small as to be invisible. Encourage everyone playing a Who to try and create his or her own, unique character.
Thing One & Thing Two - always up to something! Playful and attentive, responsible for most of the props. Works alongside The Cat
Jungle Creatures - They are real people at heart, just like us, even though they may be described as animal characters. Be imaginative. Be Wild. Be simple.
The Birds - They are like the popular kids in any school--a clique of self-centered "back up birds" who do whatever Mayzie does.
Mr. & Mrs. Mayor - Mr. and Mrs. Mayor are parents trying hard to raise a difficult child in a difficult world. They may get aggravated with Jojo, but they love him dearly and try to do the right thing, even if it turns out to be a mistake