 Mr. Carlson served in the Marine Corps as an officer, presumably during the Korean War, however, this is never explicitly stated; he also makes reference to being at Guadalcanal, as well as learning some Japanese, which may be a vague indication that he served during World War II instead.He is explicitly referenced as being 48 in an episode aired in 1979, giving him a birth year of 1931 (or possibly 1930) making Korea a much more likely.At some point he saw combat, a fact he confirmed to Venus Flytrap.