Minnesota Medal of Honor recipient Leo K. Thorsness spoke in support of presidential candidate John McCain, his former POW cellmate in Vietnam, during a press conference at the World War Memorial at the State Capitol in 2008. (The Minnesota Star Tribune)

A Medal of Honor recipient from southwestern Minnesota who shared a cell in the Hanoi Hilton prison camp for years with John McCain during the Vietnam War has died.

Retired Air Force Col. Leo K. Thorsness, a native of Walnut Grove, died Tuesday during treatment for cancer, the Medal of Honor Society said Wednesday. He was 85.

Thorsness, who lived in Alabama before moving to St. Augustine, Fla., died at the Mayo Clinic in Jacksonville, according to Huntsville, Ala., television station WHNT.

Thorsness returned to his home state in October 2016 for the society's annual convention, staged at U.S. Bank Stadium. While in Minnesota, he went back to Walnut Grove and was honored at the elementary school and had a city park dedicated in his name.

Thorsness was recognized with the Medal of Honor, the nation's highest military honor, for "demonstrated extreme courage and bravery" as a fighter pilot when he was on a mission southwest of Hanoi on April 19, 1967, the society's description of his heroics reads.

Major Thorsness "came across multiple MIG-17 enemy aircraft in his path, and while low on fuel, still managed to drive them off," the description says, "thereby helping to prevent further loss of life for his soldiers."

After damaging one enemy plane and fending off four others, he landed in Thailand.

Thorsness and his weapons specialist, Harold Johnson, "climbed out of the cockpit [and] Harry said something like 'that's a full day's work,' " Thorsness said in an interview with Air Force magazine in 2005.

Eleven days later, he was shot down on his 93rd mission and taken prisoner by the North Vietnamese. He was held for six years at the notorious prison branded by prisoners as the Hanoi Hilton, where the captives were routinely beaten and tortured, with future U.S. Sen. McCain as one of his cellmates.

He received the Medal of Honor from President Richard Nixon on Nov. 6, 1973.

In a commentary for the New York Times about his time as a POW, Thorsness wrote: "If we could bring every American to this prison for just one day, without subjecting them to torture, their appreciation for everyday freedoms would soar."

Upon his release, he soon retired from the military and was promoted to colonel.

Thorsness campaigned on behalf of McCain during the Republican senator's unsuccessful run for the presidency in 2008. He was among several veterans who appeared outside the State Capitol in St. Paul at a news conference on McCain's behalf in July of that year.

Thorsness was born on Feb. 14, 1932. His parents farmed in Walnut Grove. He attended South Dakota State University in 1950 before enlisting in the Air Force.

After retiring from the military, he ran for the U.S. Senate in South Dakota as a Republican and lost in his effort to unseat Democrat and fervent Vietnam War opponent George McGovern. He took on Democrat Tom Daschle for a U.S. House seat in 1978 and lost again. After moving to the Seattle area, he was elected to the state Senate in 1988 and served until 1992.

Survivors include his wife, Gaylee, and daughter, Dawn. Funeral arrangements have not been announced.

The New York Times contributed to this report.

Paul Walsh • 612-673-4482