Gilbert was founded in 1909 in Westville, Connecticut, originally as a company providing supplies for magic (Alfred Carlton Gilbert was a magician). Gilbert invented Erector in 1911, inspired by railroad girders, and the construction toy was introduced two years later. By 1935, Gilbert was also producing microscopes.
In 1938, Gilbert purchased American Flyer, a struggling manufacturer of toy trains. Gilbert re-designed the entire product line, producing 1:64 scale trains running on O gauge track. Although these are sometimes referred to as S scale or S gauge trains, they are technically O27. At the same time, Gilbert introduced a line of HO scale trains, which were primarily marketed under the brand name Gilbert HO.
By 1942, Gilbert was producing equipment for military aircraft for use in World War II.
Gilbert introduced S gauge model railroads in 1946, mostly in response to the shortcomings of O scale utilized by Lionel and Marx. These newer American Flyer trains were smaller and proportioned more realistically than either the pre-war American Flyer trains or its post-war competition. Although these new trains were popular, Lionel outsold American Flyer nearly 2 to 1.
Gilbert struggled somewhat after the death of its founder in 1961. Gilbert's family sold out its shares, and the company was never profitable under its new ownership. By 1967, Gilbert was out of business. Erector was sold to Gabriel Industries and American Flyer was sold to Lionel.