The Leftorium is owned by Ned Flanders, who had quit his job as a pharmaceutical company clerk to open the store. At first, business at the Leftorium was very poor, due to Homer's secret wish that Flanders' store would go out of business. Homer got his wish and the Flanders family were forced to sell their personal possessions (much of which Homer purchased at a cost of $75); the bank repossessed the Flanders home; and the store was about to close. Homer later regretted making this wish and never telling any of his friends who were in need of left-handed items about The Leftorium. To atone for his misdeeds, Homer manages to get everyone he knows in town to shop at Ned's store, effectively saving it from bankruptcy.The Leftorium was looted by a mob after a hurricane struck Springfield.
The Leftorium has continued to trade profitably since. However, there have been episodes during which Flanders mentioned the store is not doing so well. Ned once mentioned that he purchased most of his personal possessions cheaply to make up for his store's lack of business. Ned also mentioned that a left-handed megastore that had recently opened, Left-Mart, is threatening his business. It has bullet proof windows. Some people consider the store a "rip-off" due to some items only being labeled as "left-handed" without truly being manufactured solely for left-handers, e.g., left-handed remote controls, left-handed pens left-handed cellphones, etc. Eventually Ned had to downsize to a simple kiosk, the Leftorium Express, due to the success of a nearby full-sized competitor, Southpaw Superstore. However, in the episode Opposites A-Frack, Ned is seen working in his full-sized store once again without a continuity explanation.
The abundance of left-handers in Springfield is likely due to the show's creator, Matt Groening, being himself left-handed. Groening revealed in the DVD commentary for When Flanders Failed that about 1 in 3 Springfieldians are left-handed, as compared to about 1 in 9 in real life.
- Episode – "When Flanders Failed"
- Episode – "Hurricane Neddy"
- Episode – "In Marge We Trust"
- Episode – "Thirty Minutes Over Tokyo" (mentioned)
- Episode – "Last Tap Dance in Springfield" (cameo)
- Episode – "A Star Is Born-Again"
- Episode – "Dude, Where's My Ranch?" (mentioned)
- Episode – "Home Away From Homer" (mentioned)
- Episode – "The Great Wife Hope" (billboard mention)
- Episode – "Opposites A-Frack"
- Video game – The Simpsons Road Rage