Leo was born on the 14th of February, 1932, in Walnut Grove, Minnesota, and grew up on his family’s farm. He was an active member of the Boy Scouts, eventually becoming an Eagle Scout and after high school, he attended South Dakota State College. Leo enlisted in the US Air Force in 1951 at the same time that his brother was serving in the Korean War and he went on to receive a commission and his pilot wings after completing the Aviation Cadet program with Class 54-G. He then went back to school and graduated from the University of Omaha in 1964 and then from the University of Southern California with a master’s degree in Defense Systems Management. Leo transitioned from the Strategic Air Command and Tactical Air Command to being a fighter pilot, flying both F-84 and F-100 jets and then on to the F-105 Thunderchiefs.

In late 1966, Leo was assigned as an aircraft commander with the 355th Tactical Fighter Wing in Thailand and it was his actions on the 19th of April, 1967, while on a mission to locate and destroy North Vietnamese surface-to-air missile sites, that would earn him the Medal of Honor. The citation reads:

For conspicuous gallantry and intrepidity in action at the risk of his life above and beyond the call of duty. As pilot of an F-105 aircraft, Lt. Col. Thorsness was on a surface-to-air missile suppression mission over North Vietnam. Lt. Col. Thorsness and his wingman attacked and silenced a surface-to-air missile site with air-to-ground missiles, and then destroyed a second surface-to-air missile site with bombs. In the attack on the second missile site, Lt. Col. Thorsness' wingman was shot down by intensive antiaircraft fire, and the two crewmembers abandoned their aircraft. Lt. Col. Thorsness circled the descending parachutes to keep the crewmembers in sight and relay their position to the Search and Rescue Center. During this maneuver, a MIG-17 was sighted in the area. Lt. Col. Thorsness immediately initiated an attack and destroyed the MIG. Because his aircraft was low on fuel, he was forced to depart the area in search of a tanker. Upon being advised that two helicopters were orbiting over the downed crew's position and that there were hostile MIGs in the area posing a serious threat to the helicopters, Lt. Col. Thorsness, despite his low fuel condition, decided to return alone through a hostile environment of surface-to-air missile and antiaircraft defenses to the downed crew's position. As he approached the area, he spotted four MIG-17 aircraft and immediately initiated an attack on the MIGs, damaging one and driving the others away from the rescue scene. When it became apparent that an aircraft in the area was critically low on fuel and the crew would have to abandon the aircraft unless they could reach a tanker, Lt. Col. Thorsness, although critically short on fuel himself, helped to avert further possible loss of life and a friendly aircraft by recovering at a forward operating base, thus allowing the aircraft in emergency fuel condition to refuel safely. Lt. Col. Thorsness' extraordinary heroism, self-sacrifice, and personal bravery involving conspicuous risk of life were in the highest traditions of the military service, and have reflected great credit upon himself and the U.S. Air Force.

Almost two weeks later, Leo and his Electronic Warfare Officer, Harold Johnson, were on their 93rd mission when they were targeted and hit with a heat-seeking missile from a MiG-21. They both ejected from the jet and were separated by a ridge while a three hour rescue mission took place for them, which ended due to high MiG engagements. Leo and Harold were captured and held as prisoners of war and Leo’s actions towards his captors earned him a year in solitary, as well as severe back injuries from the torture that they would subject him to. The decision to award Leo the Medal of Honor happened while he was in captivity but was never made public for fear that it would be used against Leo by his captors. Harold and Leo were both released from captivity on the 4th of March, 1973 after almost six years as prisoners. Harold received the Air Force Cross for his actions during the same April 19th mission and Leo received the Medal of Honor from President Nixon on the 15th of October, 1973, in a ceremony at the White House. Due to the injuries he sustained during both the ejection from the jet and the torture from the enemy, Leo was medically disqualified from flying and he retired from the Air Force at the rank of Colonel and with 5,000 flying hours on the 25th of October, 1973.

After the military, Leo dove into the political ring, losing his first campaign to South Dakota Senator George McGovern in 1974. He then was elected to the Washington state senate in 1988 and sponsored a bill that successfully forced the federal government to declassify information connected to 30,000 missing American service members, dating back to World War 2. He served one term before retiring and serving on the Board of Directors for the Congressional Medal of Honor Foundation. Surviving Hell: A POW’s Journey, was Leo’s autobiography that published in December of 2008, and on the 2nd of May, 2017, Leo Keith Thorsness died at the age of eighty-five. He is buried in Arlington National Cemetery: Section 60, Site 11721.