The first mechanical mower was patented in 1830 by Edwin Budding. The Budding mower introduced the design concept of the reel mower, later used in early Lawn-Boy mowers. In 1859, the Silens Messer mower replaced the Budding gears with a chain drive, another feature of vintage Lawn-Boy power mowers. Edward Ransome patented the first lawn mower with a gasoline engine in 1902. By 1925, millions of hand-pushed reel mowers were in use. By the late 1920s, gas-powered reel and rotary mowers dominated the market.
In 1907, Ole Evinrude founded a company that would eventually become Lawn-Boy. After being sold to Briggs and Stratton, Evinrude Motors was merged with several other companies into the Outboard Motor Corporation in 1926. Ole Evinrude died in 1934, passing the presidency of the Evinrude Company to his son, Ralph. It was under Ralph that the first Lawn-Boy brand power mower was manufactured by Evinrude and introduced to the American market in 1934.
The 1934 Model "D," or Deluxe Lawn-Boy, was billed as America's first self-propelled, one-handed, reel power mower. It was controlled and steered by a single metal handle with a pivot joint in the middle. The start-and-stop control was located in the steering handle grip. The mower had an 18-inch wide cut and featured a height-adjustable roller, ranging from 1/2 to 1 1/2 inches. The Model "D" sold for $110.
In 1938, the Model "S" Lawn-Boy was introduced. The one-handed, diamond-roller-chain-driven mower was speed adjustable to fit the mower's walking pace. A yard of 3 acres could be cut in a day, using 1/2 gallon of gasoline to run the mower for 5 to 7 hours. A 6-inch diameter rotating reel outfitted with 5 carbon-manganese alloy steel blades and a chrome alloy cutter bar provided efficient cutting power. The mower rode on 10-inch-diameter rubber tires.