Thorsness received the Medal of Honor for his actions in the Vietnam War. He was awarded the medal for an air engagement on April 19, 1967. He was shot down two weeks later and spent six years in captivity in North Vietnam as a prisoner of war with future United States Senator John McCain. After his military service, Thorsness served one term in the Washington State Senate from 1988 through 1992 after beating the current State Senator Eugene V. Lux. He was a Republican.