As a 19-year-old, Ashford finished 5th in the 100 m event at the 1976 Summer Olympics. After beating the World Record holders in the 100 m and 200 m in 1979, Ashford was one of the potential gold medalists for the 1980 Summer Olympics, but these Games were boycotted by the United States.
In 1983, she first set the World Record in the 100 m at 10,79, and wanted to win the 100 m title at the inaugural World Championships in Helsinki. In the final, however, she pulled a hamstring muscle, fell and gave up.
At the 1984 Summer Olympics, Ashford finally had a chance to win a gold medal, especially since the East Germans boycotted the Olympics. But Ashford became injured shortly before the Games and had to withdraw from the 200 m heats. She did compete in the 100 m, and with success, winning the event in a new Olympic Record. As the final runner for the relay team, she won a second gold medal. Later in the season, she defeated the East German women while setting a World Record.
At the 1988 Summer Olympics, she was beaten in the 100 m by Florence Griffith Joyner, who had broken her World Record earlier at the Olympic Trials. In the 4 x 100 m, she again ran the final leg, winning her third Olympic gold medal in spite of a sloppy exchange.
At her last Olympics, in 1992, Ashford was eliminated in the 100 m semi-finals, but won her third straight Olympic 4 x 100 m relay title.