Zaphod Beeblebrox's1 parentage is a little difficult to explain. His mother is Mrs. Alice Beeblebrox (of 10 to the 8th Astrel Cresent, Zoovrooselchester, Beeteljuz 5), while his father is Zaphod Beeblebrox the second. 2
Time as Galactic President
It is not generally known exactly when Zaphod became president,3 but what is known is that he became it as part of a plan, made up by a group consisting of Zaphod, Rooster and Zarniwoop, to find out who the person making all the decisions behind the President's back.
The Plan aws as follows: Zaphod was to forget everything about the plan 4, become president, then steal the first Improbability Drive ship. He would then bring this into the Universe that had been created in Zarnewoop's office (on the 5th floor of the Hitch-Hickers Guide offices, Ursia Minor Beta), so that they could find the man.