He was briefly the President of the Galaxy. He has had an extra head and arm attached, meaning he now has two heads and three arms (the radio series hints that he later acquires a fourth arm). He invented the Pan Galactic Gargle Blaster, and is the only person able to drink more than two of them at one sitting. He is from a planet in the vicinity of Betelgeuse, and is a "semi-cousin" of Ford Prefect (with whom he 'shares three of the same mothers').
He is the only man to have survived the Total Perspective Vortex, although it may only have been a replica of the real Vortex.
In both the radio and television versions of The Hitchhikers Guide to the Galaxy Zaphod was played by Mark Wing-Davey. In the television version he wore a false arm (when the arm was required to gesture it was replaced by the arm of someone else standing behind Wing-Davey) and a radio-controlled second head with an eyepatch. Unfortunately the second head's mechanics seldom worked properly and so for most of the time it just sits on his shoulder looking inanimate, although in one scene it manages to have a brief conversation with Wing-Davey's real head.