In April 1972, Norris was one of few remaining SEALs in Vietnam. When Lt.Col. Iceal Hambleton was shot down behind enemy lines, aerial combat search and rescue operations failed, leading to the loss of five additional aircraft and the death of 11 or more airmen, two captured, and three more down and needing rescue. Norris was tasked with mounting a ground operation to recover Lt.Col. Hambleton, 1stLt. Mark Clark (the son of World war II General Mark W. Clark), and 1stLt. Bruce Walker from behind enemy lines. Assisted by Vietnamese Sea Commando forces, he and VNN Petty Officer Nguyen Van Kiet went more than 2 kilometers (1.2 mi) behind enemy lines and successfully rescued two of the downed American aviators. Walker was discovered and killed by the NVA. Though he at first rejected the honor, he was recognized with the Medal of Honor in 1975. His actions were dramatized in the movie Bat*21.
Six months later, in October 1972, Norris sustained a near-fatal head wound in combat while protecting forces evacuating to his rear. A South Vietnamese soldier saw his severe head injury and left him, believing that Norris was dead. Fellow Navy SEAL Michael E. Thornton, upon hearing the news, went back intending to recover the body of his fallen comrade, only to discover that Norris was still just barely alive. Thornton was recognized with the Medal of Honor for his actions; he was the first person in more than a century to receive the Medal of Honor for saving the life of another Medal of Honor recipient. Norris received the Medal of Honor from President Gerald R. Ford in a White House ceremony on March 6, 1976.
Tom Norris lost an eye and part of his skull during the combat in which he was rescued by Michael Thornton. As a result of the head injury, he retired from the Navy. He then spent three years recovering from his injuries in the hospital and over a six-year period underwent many major surgeries. In 1979, Norris joined the FBI and requested a waiver for his disabilities. FBI director William Webster responded, "If you can pass the same test as anybody else applying for this organization, I will waive your disabilities." In September 1979, Norris passed the test and subsequently served as an FBI agent for 20 years. He was an original member of the FBI's Hostage Rescue Team as an assault team leader. He is a member of the Society of Former Special Agents of the Federal Bureau of Investigation.