The generically named doll is an ordinary-looking representation of a young girl with curly blond hair and a variety of outfits.
She began to feature in the early 1990s when Betty Lou's appearances became more prominent. In Episode 3205, she explains to Big Bird that her dolly's head comes off all the time. She recalls past activities with her dolly that caused her head to come off. At first, Betty Lou would cry, until her mommy and dad fixed it. Eventually, she was able to do it herself and is used to it when it happens.
The next year, in Episode 3273, the loss of her dolly's head becomes a crisis for Betty Lou as she doesn't notice when it goes missing. Telly Monster helps her look for it, and Gina suggests they put up signs for the doll's missing head. Several residents of Sesame Street bring doll heads to Betty Lou, but none of them is a match. Finally, Angela and Jamal happen upon Zoe playing with Dolly's head in the park, and direct her to Hooper's Store, where it is reunited with its body.
In Episode 3215, Dolly accompanies Betty Lou to day care, where Dolly helps Betty Lou transition into her first day. Dolly also appears in Episode 3158 and Episode 3413, and in the book No More Diapers! (1995). Betty Lou had previously been seen with a similar doll in My Doll Is Lost! (1984), and another doll is used as a prop for Betty Lou's story "Dolly Dearest" in Episode 3535.