Born in York, Maine, Margaret E. "Mattie" Knight, nicknamed "Lady Edison," spent her childhood in Manchester, New Hampshire, where she received a meager education. Estranged from the usual pastimes of little girls, she made homemade kites and sleds, which were the envy of the neighborhood. At age twelve, while observing her brothers at work in a cloth factory, she saw a large metal-tipped shuttle drop from the loom, endangering a worker. This incident motivated her to devise a stop-motion device to prevent loom accidents.

As an adult, Knight moved to Springfield, Massachusetts, and worked for a manufacturer of paper bags. After studying the operation, in 1867 she devised a mechanism that produced a bag with a square bottom, which would enable users to load the bag without holding it erect. Two years later, she took her idea to Boston and began putting the finishing touches on the device so that it could be patented. Another inventor, Charles F. Annan, copied her idea and applied for his own patent. Knight contested his claims in court and won her suit in 1870.

For most of her productive years, Knight lived in Ashland and Framingham, Massachusetts, but she also maintained a workshop in Boston, and was associated with the Knight-Davidson Motor Company of New York. She created a number of handy domestic gadgets, including various machines that cut out and sewed shoes, a window sash and frame, a dress and skirt shield, a barbecue spit, a clasp for holding robes, and a numbering device. Late in her career, she studied rotary engines and evolved a sleeve-valve engine, a horizontal variation on the vertical poppet valve, which was posthumously patented in 1915. The return for her work, however, brought her small profit; she died of pneumonia and gallstones in 1914, leaving behind an estate valued at less than $300.