A 1966 graduate of Miss Porter’s School and a 1970 graduate of Hollins University in Roanoke, Virginia, she defeated Anne Quast to win the 1973 U.S. Women’s Amateur at the Montclair Golf Club in Montclair, New Jersey. Semple won the 1974 British Ladies Amateur. At present, she is one of only eleven golfers to hold both titles. In defense of her U.S. championship, she made it to the 1974 finals but lost to Cynthia Hill. Among her other significant victories in amateur play, she won the 1976 and 1987 North and South Women’s Amateur, two U.S. Women’s Mid-Amateurs, and won the U.S. Senior Women’s Amateur four years in a row from 1999 to 2002.
She also was part of the American team that won four Espirito Santo Trophys at the World Amateur Golf Team Championships. She is also one of only five people to have won three different USGA individual championship events, the others being JoAnne Carner, Jack Nicklaus, Arnold Palmer, and Tiger Woods.
Semple Thompson was voted the 2003 Bob Jones Award recipient, the highest honor given by the United States Golf Association in recognition of distinguished sportsmanship in golf.