In 1943, Richard James, a naval mechanical engineer stationed at the William Cramp and Sons shipyards in Philadelphia, was developing springs that could support and stabilize sensitive instruments aboard ships in rough seas. James accidentally knocked one of the springs from a shelf, and watched as the spring "stepped" in a series of arcs to a stack of books, to a tabletop, and to the floor, where it re-coiled itself and stood upright. James's wife, Betty, later recalled, "He came home and said, 'I think if I got the right property of steel and the right tension; I could make it walk.'"
James experimented with different types of steel wire over the next year and finally found a spring that would walk. Betty dubbed the toy Slinky (meaning "sleek and graceful").
Richard James opened shop in Albany, New York, after developing a machine that could produce a Slinky within seconds. The toy was packaged in a black-lettered box, and advertising saturated America. James often appeared on television shows to promote Slinky. In 1952, the Slinky Dog debuted. Other Slinky toys introduced in the 1950s included the Slinky train Loco, the Slinky worm Suzie, and the Slinky Crazy Eyes.
Over 300 million Slinkys have been sold between 1945 and 2005, and the original Slinky is still a bestseller.