She entered and completed the race in 1967, five years before women were officially allowed to compete in it. Her finishing time of approximately 4 hours and 20 minutes was nearly an hour behind the first female finisher, Bobbi Gibb (who ran unregistered). She registered under the gender-neutral "K. V. Switzer"
Race official Jock Semple attempted to remove her from the race, and is noted to have shouted, "Get the hell out of my race and give me those numbers." However, Switzer's boyfriend Tom Miller, who was running with her, shoved Semple aside and sent him flying. The photographs taken of the incident made world headlines.