One of the world’s leading sprinters of the 1940s. Although he was believed to be past his prime when the Olympic Games were resumed after World War II, he won three medals at the age of 30 at the 1948 Olympics in London. He first achieved renown while a student at Pennsylvania State University, running the 100- and 200-metre races and winning 12 gold medals and championships in collegiate meets between 1940 and 1942; he also won 11 gold medals in Amateur Athletic Union national meets between 1939 and 1948. He was an outstanding long jumper as well, leaping 25 feet 2 inches (7.68 m) in 1942. 

During the trials for the 1948 Olympics, Ewell tied the world record of 10.2 seconds in the 100-metre dash. At the Games themselves, Ewell won two individual silver medals. He came from behind to finish a close second in the 100-metre dash; he then led for most of the 200-metre dash, only to fall back in the home stretch. He led off the U.S. team that easily won the 400-metre relay, but the victory was initially ruled void because Ewell appeared to hand the baton to a teammate outside the passing zone; after viewing a film of the race, however, officials reversed the ruling, giving the Americans the gold medal.