[2][3][4] In early stages of development for Inside Out, Joy was going to be the main source of narrative tension as she wouldn't let Riley grow up.

[6][7] From the early stages of production, director Pete Docter was set on Joy being the film's protagonist, as reason for why she is the only emotion with a common name.

[8] Docter has said Joy was the hardest character to write in the film, due to her positive attitude potentially grating on people, so her contrast with Sadness and development from it was given a major role in the story to avoid this.

[12] According to designers, Joy was given bare feet and a pixie cut to reinforce her "rambunctious" nature, as well as a blue hair color to avoid comparisons to the Peter Pan character Tinker Bell.

[14] As her name would suggest, Joy is vivacious and has a cheerful, peppy and optimistic attitude, mainly wanting the best for Riley.

[15][16] While she thinks of herself as a people person, Joy grows easily frustrated with anyone who doesn't share her worldview.

Riley's world is turned upside down when her family move from Minnesota to San Francisco, California.

The move causes the other emotions to act up, but Joy is able to remain in control of headquarters, however when she and Sadness get into a struggle, they accidentally end up in the distant part of the brain and have to find their way back.

Sadness makes Riley remember all of these memories one by one, and takes control of the panel, and Riley finally reveals her true feelings to her parents - she hates San Francisco, misses the good old days in Minnesota, and that she was pretending to be happy, and was afraid of making them mad because she has always been their "happy girl."

Riley's parents admit they feel the same way, and a brand-new core memory is made; it is a mix of happiness and sadness.

[32] Joy's cheerful personality itself proved popular but her journey and development throughout the film also received much acclaim, notably her realization of sadness being essential.

Bilge Ebiri of Vulture said "The more I watch Inside Out, the more I realize just how much of the film rests on Poehler's shoulders.