Tootie is a little girl who is madly in love with Timmy. She is the stereotypical geeky girl who wears distinctive purple glasses with a thick cat's eye shaped frame (sometimes seen with more ordinary, round glasses), and has braces on her teeth. She wears very dull colored clothing compared to the bright colors of other characters, a black and white blouse and a gray plaid skirt with black tights underneath. Without glasses, Tootie has purple eyes, but she's mostly seen with her glasses on, as she doesn't have very good eyesight. Her tone of voice is squeaky, nasally and sometimes she laughs with a pausing "Mandark" type laugh when she's overexcited. As she ages, however, Tootie becomes more beautiful, and her voice becoming less squeaky. As a teenager, Tootie loses her braces and has a voice similar to Frankie Foster from Foster's Home for Imaginary Friends. When Tootie became an adult, she no longer wears glasses and uses contacts instead.
Tootie's personality is based on that of the stereotypical fan girl. She is obsessed with the main character, has tons of Timmy-related store bought merchandise (even though Timmy is not famous), dreams of kissing him and eventually marrying him, and gets a bit jealous when she sees Timmy with another girl, like Trixie or Veronica. This was toned down a bit in the second season, and after the events of "A Mile In Popularity's Shoes", her stalking habits stopped. Tootie is a kind and caring girl, especially compared to her meaner older sister Vicky. She feels sorry for people with poor eyesight, and offered to give them her glasses, as was the case with Ivan Prestonovich in the first episode.