1963 Harley-Davidson Sportster. In 1963, Willie G Davidson (son of founder Arthur Davidson) joined the Harley-Davidson family firm as Director of Design. By then, 120,000 miles of super-highway had been constructed across the United States and was rapidly changing the face of motorcycling culture, the rider's demand for high-performance, long-range machines drew race technology from the track onto the street at an unprecedented pace, the T120 Bonneville was gaining significant market share and Harley-Davidson, now America's longest-standing motorcycle company, responded to British muscle head-on with what is now considered to be a signature design: the light and powerful XLH Sportster.