A member of the African-American 10th Cavalry commonly known as the "Buffalo Soldiers," Private William Thompkins served in the Spanish-American War. On June 30, 1898, he and three other black soldiers participated in a daring rescue of wounded troops near Tayabacoe, Cuba. After three failed attempts by other units, Thompkins and his comrades voluntarily rowed a boat ashore under heavy enemy fire, retrieved the American and Cuban soldiers, and returned to their transport ship without taking any losses. All four privates were awarded the Medal of Honor. He is buried in the San Francisco National Cemetery at the Presidio.
Thompkins is buried in West Side, Grave 1036A.