The Horseless Carriage was made by Alexander Winton, a Scottish immigrant who began building cars by hand after incorporating the Winton Bicycle Company in 1897. The vehicle had painted sides, a leather roof, padded seats and tires supplied by B.F. Goodrich. It boasted a whopping 10 hp and a top speed of just over 33 miles per hour.
Winton had taken out advertisements in Scientific American for his horseless carriage and sold 22 of them in 1898, including one to James Ward Packard who would later found the Packard automobile company. Packard was supposedly so dissatisfied with the Winton Horseless Carriage he started his own company after Winton challenged him to do better.
Winton had a successful few years with his motor company. In fact, Winton sold so many cars that it led to the opening of the first car dealership in 1899 in Reading, Pennsylvania and the production of the first auto hauler. However, the company ultimately stopped producing cars in 1924. Winton continued in the engine business for a while, designing and manufacturing marine and stationary gasoline and diesel engines. He sold to General Motors in 1930.
Although the Winton name has been forgotten by many, there's no question that this man and his company had a profound effect on the American auto industry.
UPDATE: We originally published this stating that the Winton Horseless Carriage was the first automobile sold in the U.S. In fact, that distinction belongs to the Duryea Motor Wagon, which was built and sold two years before the Winton.