Colonel Walter Rudolph Walsh (born May 4, 1907) is a former FBI agent, USMC shooting instructor and Olympic shooter. Walsh joined the FBI in 1934, serving during the Public enemy era, and was involved in several high-profile FBI cases, including the capture of Arthur Barker and the killing of Al Brady. He served in the Pacific theatre during World War II with the Marine Corps and, after a brief return to the FBI, served as a shooting instructor with the Marine Corps until his retirement in the 1970s.
A high profile shooter, Walsh won numerous tournaments within the FBI and the Marine Corps, as well as nationally, and participated in the 1948 Summer Olympics. He received awards for his marksmanship until the age of 90 and served as the coach of the Olympic shooting team until 2000. At the FBI's 100th anniversary celebration he was recognized as the oldest living former agent and noted as being a year older than the organization itself. Aside from some hearing and memory loss, he remained physically fit at his 102nd birthday.