 His first ultra-marathon was the 100-mile Western States run in Squaw Valley, California.In all, he completed 23 marathons, eight 50-mile ultra-marathons and fourteen 100-mile ultra-marathons.Upon his retirement from the University of Florida, the City of Gainesville and Alachua County, Florida, honored him by declaring August 14, 1994 as Dr. Ngo Dong Day.