Toaster was a good friend of Rob, the Master, who took pleasure in having him see his reflection in her silver faceplate and making faces as he waited for his toast to cook. After the Master left several years ago, Toaster was one of the few appliances in the house who never lost faith in the Master's eventual return.
One day, while Toaster and her four friends, Kirby, Lampy, Radio, and Blanky are cleaning the cottage, they see a man outside their window putting up a "For Sale" sign, leading them to believe that the Master would never return. Fed up and in denial that the Master would deliberately abandon them, Toaster declared that she and her friends would go out to find him. Despite initial reluctance, they eventually all agree, and set out into the wilderness. They come across many dangers along the way, but Toaster retains her optimism and hope, even when all seemed lost.
Eventually, they are found by an appliance repair man after nearly drowning in a swamp. The repair man tries to dismantle Radio, but after scaring the repair man and rescuing Radio, they escape, making it to the apartment where the Master now lived. There, they are derided and thrown out by the Master's new appliances, who all believe themselves to be far more modern than Toaster and her friends. They are hauled off to the junkyard to await disposal.
Unknown to Toaster and the other appliances, the Master actually returned to the cottage, hoping to collect his favorite appliances for use in college. When he did not find them, he and his girlfriend Chris journeyed to the junkyard to dig up some spare appliances, since the Master did not love the modern appliances as he did his old ones. While there, he finds most of his appliances, who have been dodging an evil magnet crane determined to destroy them. The Giant Magnet nearly causes the Master to get crushed by the Crusher, but Toaster sacrifices herself by throwing herself into the gears, jamming them and stopping the Crusher, saving her Master's life. Upon returning home with all of his appliances, the Master fully repairs Toaster, and makes faces in his faceplate like he did as a kid. Toaster and her friends accompany their friend to college, happy to serve him once again.
Toaster is now living a happy life with the Master at his college, having become good friends with the animals the Master is caring for, along with the Dobermans working with the campus security. However, Toaster soon learns that the Master's thesis he was working on has been lost, and at the suggestion of Sebastian, they attempt to look for it on the computer in the clinic, learning about the Internet, before the computer is infected by a virus infecting the prototype TLW-728 supercomputer Wittgenstein, causing her to reveal that Sebastian and the other animals are to be shipped out to Tartarus Laboratories. Hoping to help both the animals and the Master, Toaster, aided by Radio, Blankey, Lampy, and Ratso, travel to the basement and meet Wittgenstein. Upon learning that he is down to his last tube, the extremely rare WFC-11-12-55 cathode tube, Toaster hopes they can help Wittgenstein, but an argument between Radio and Ratso regarding finding the tube in the college storage warehouse results in it being shattered, with blame being pinned on Radio. When Wittgenstein learns from the clinic computer that the animals are about to be shipped out, he struggles to try and help, but the virus proves too much for him and he blows his last tube, seemingly killing him.
Toaster and the others are angry with Radio for dooming the animals and Wittgenstein, but as they cry and fear their friends are goners, Radio gives them a last chance as he sacrifices his own tube, also a WFC-11-12-55, to revive Wittgenstein to full health, destroying the virus and putting Wittgenstein back in his prime. With Wittgenstein's aid, Toaster and the others pursue Mack McCro and Jim Bob, and catch up to the truck before police and the Master arrive. Mack and Jim Bob are arrested, the animals are saved, and sometime later, Toaster watches while wearing the Master's graduation cap as the Master proposes to Chris and she accepts, and Chris provides a new WFC-11-12-55 to revive Radio that was found in Nome, Alaska.
With the animals all getting good homes, and Ratso coming with Toaster, her friends, the Master, and the new Mistress, the gang set off for their new life together.
- In the Timon & Pumbaa series, during Timon and Pumbaa's music video of "Stand by Me", a toaster that resembles the Toaster is seen.
- There is a cameo of Toaster and friends in the series The Oz Kids, in the episode "Christmas in Oz".
- According to the original novella, Toaster is a Sunbeam.
- The Toaster is a female. Ironically, while the Toaster is referred to as "she" in the movies, "her" voice actress Deanna Oliver calls the Toaster "she" and "her." Thomas M. Disch refers to Toaster as "it".
- Toaster is one of very few female characters to be voiced by females, including Stanley from the television series of the same name (as voiced by Jessica Stone), Lester from the same show (Philece Sampler), Huey, Dewey and Louie (Pamela Adlon and E.G. Daily in Quack Pack and Russi Taylor just about otherwise; though they are sometimes voiced by actual men using childlike voices), Rolly and Lucky in 101 Dalmatians (both film and TV series), Binky Bevel from Rolie Polie Olie (Sunday Muse), Honker Muddlefoot in Darkwing Duck (Katie Leigh), Beary in The Country Bears (of course, this applies to his singing voice alone), and Robbie in The Brave Little Toaster Goes to Mars (Russi Taylor again).
- Also, the Toaster is voiced by a man in the German, Latin Spanish, Finnish, Russian, and Croatian dubs.