Deep Six's real name is Malcolm R. Willoughby, and his rank is that of Navy Petty Officer 2nd class (Master Diver's rating). Deep Six was born in Baltimore, Maryland.
Deep Six's primary military specialty is diver, and his secondary military specialty is small craft pilot/motorized. He likes to be alone, preferably down in the ocean depths. He was one of the twelve out of 50 applicants who passed the strict requirements for the position of the Joe Tram diver; eight more washed out in the practical application testing, and of the four finalists Deep Six could hold his breath the longest.
Sunbow Deep Six appeared in the original G.I. Joe animated series. He is portrayed as a recluse. He first appeared in the animated series in the first season episode "Cobra Stops the World". He was voiced by Hal Rayle.
Deep Six appeared in two public service announcements. The first one dealt with him saving a kid from drowning while explaining the horrors of not wearing a lifejacket. The second one dealt with him telling kids the horrors of swimming during a thunderstorm.