In the first film, Kirby reluctantly joins the appliances on a mission to find Rob, who is referred to them as "the Master." While although seemingly cantankerous and bossy towards the others, he actually cares very much about them, and risks his life to save them more than once. Kirby cannot help but keep up the appearance that he is independent and being held back by the others.
Being grumpy and stubborn, Kirby doesn't hang around much with the other appliances until near the very end of the first movie. He utterly despises Blanky and his overly-emotional personality. Kirby starts to soften up as the film progresses. In the movie's sequels, he is more laid-back and closer to his fellow appliances.
Kirby is named after the brand "Kirby," but when in the novel, he is named after the brand "Hoover."
In Disch's original novella The Brave Little Toaster Goes to Mars, the Kirby and Lampy stayed behind while Toaster, Radio and Blanky went on the mission. In the film, they join them on the quest.
There is a cameo of Kirby and friends in the series The Oz Kids in the episode "Christmas in Oz".