Jojo is only given a distinct personality in the Illumination feature film adaption of Horton Hears a Who, and Seussical the Musical.
Jojo is the son of Ned McDodd and he is oldest child, as well as the only boy, among the Mayor's 97 children, and will more than likely be the future mayor of Whoville, because in Whoville tradition "the oldest is next in the mayoral line". JoJo is also the smallest Who of all.
JoJo is so worried that he'll say something to disappoint his father that he finds it best not to speak- ever. But he's anything but silent. He hears music in the tapping of an old keyboard, feels the beat in the rhythmic bounce of a basketball and finds harmony in wind whistling over a comb.
It is later revealed that JoJo takes nightly excursions to the Abandoned Star-Study Tower, and the one time we see him about to leave, his arms are filled with various odds and ends (including an umbrella that looks remarkably like that of the Cat in the Hat's), are to work on what is rather literally a giant instrument (called "the Symphonophone" on the soundtrack): he had filled the observatory with these castaway items and set up an elaborate system to produce music. JoJo uses his Symphonophone to add to the ruckus needed to alert the citizens of Nool to their existence, in addition to his signature cry: "YOPP!"
Seussical the Musical
In Seussical the Musical, Jojo is the protagonist, and acts as an energetic young boy (or sometimes girl, depending on the production) with big ideas. He is curious, and often gets into trouble. He befriends Horace, who has similar problems to him.
In the special, JoJo is blond, has blue eyes, and wears an all-blue outfit with a red bow at his neck.
Seussical the Musical
Jojo also appears in Seussical the Musical as the protagonist. Jojo keeps getting in trouble for having different thoughts and big ideas. The Cat in the Hat also keeps popping up and getting him into even more trouble. He then meets Horton, who also has problems because of his big ideas (And of course because he thinks there are people on a speck of dust).
- He only has four to five lines lines in the film:
- (silently mocking his dad) "Good talk."
- "Dad, you're one of the greats!"
- "What are we gonna do without you, Horton?"
- (singing) "I can't fight this feeling any-MORE!!!!"
- Technically in the Illumination Film, the statment that he is the smallest Who is incorrect, as Hedy, his youngest sister, is smaller than he is. However this may be due to her young age, while JoJo is still smaller than the rest of his sisters.
- JoJo's singing voice at the end of the film is provided not by Jesse McCartney, but by session singer Fletcher Sheridan, who was in another Dr. Seuss film, The Lorax, as Cy, the O'Hare delivery guy.