Glenn served as a Marine pilot in World War II and the Korean War. He flew 59 missions in the F4U Corsair in the last year of World War II, and flew the F9F Panther and F-86 Saber over Korea, shooting down three MiGs in the Saber. On February 20, 1962, Glenn became the first American to orbit the earth, doing so three times in the space capsule Friendship 7.
Glenn has been awarded the Distinguished Flying Cross on six occasions, and holds the Air Medal with 18 Clusters for his service during World War II and Korea. Glenn also holds the Navy Unit Commendation for service in Korea, the Asiatic-Pacific Campaign Medal, the American Campaign Medal, the World War II Victory Medal, the China Service Medal, the National Defense Service Medal, the Korean Service Medal, the United Nations Service Medal, the Korean Presidential Unit Citation, the Navy's Astronaut Wings, the Marine Corps' Astronaut Medal, the NASA Distinguished Service Medal, and the Congressional Space Medal of Honor. 
In 1976, Glenn was a candidate for the Democratic vice presidential nomination. However, Glenn's keynote address at the Democratic National Convention failed to impress the delegates and the nomination went to Senator Walter Mondale. Glenn also sought the 1984 Democratic presidential nomination.
In a 2009 interview in Audiology Today he expressed approval for good health care available for everyone. During the Korean war he flew 63 missions. His head gear provided some hearing protection as a pilot and astronaut. He wears hearing aids and believes his high-frequency hearing loss is from aging rather than noise exposure. When his Mercury space ship was descending to sea level, he had to keep adjusting the air pressure in his ears by moving his jaw. He also adjusts his ears when scuba diving. After his three orbits around the earth, he wanted to go into space again, but wasn’t allowed to because of the danger of space flight. He worked for the space program another two years until he bumped his head on the edge of his tub. He was hospitalized for a while and had dizziness for almost a year. Because of his fame, he was able to become a U.S. Senator. He joined the committee on aging to help his parents and the aging population. His is opposed to space tourism and wants the space station to continue to do research even if there is another mission to the moon. He went on a space shuttle mission when he was 77 for research on aging. He is fine with women being allowed to be test pilots and astronauts, but considers space flight to be as risky as combat missions. He has never seen what he considers to be a UFO and is open-minded when told about UFOs.
- Fabry, D. 2009. Rocket Man John Glenn. Audiology Today. Reston, VA: American Acadamy of Audiology.
The New American Desk Encyclopedia, Penguin Group, 1989
- Biography at Acepilots.com