Gerald's past is a mystery, even to Daniel Struthers, the latest member of the Struthers family he accompanies. All that is known is that Gerald follows members of the Struthers family around, though it isn't especially known why. He isn't programmed to do so and it seems quite out of character for him to be so obedient and helpful.
When asked, he says that he hasn't got anything better to do, which is mostly true as robots can't really make a life of their own in the Wasteland and often get torn apart for scrap metal. It's possible that serving the Struthers family keeps him protected and sane.
He reveals to Talulah that he has little recolection of being in the Vault. In fact, it's so hard to remember that time that he asks Struthers to write his memories down. From what he can recall, his borish attitude is nothing new, hinting that part of the Vault experiment was having disobedient robots. Gerald often responded with foul mouthed abuse, in response to simple questions.
In 2289, Gerald is following Daniel Struthers as he goes to the islands of Hawaii to see what potential awaits them.
Gerald is an unusual Mr Handy, who has a cockney accent. It is unknown why he has this voice module, if it was part of the Vault experiment or if it was part of his escape, after Struthers liberated him. Either way, Gerald is borish, obnoxious and also quite violent and sociopathic. Gerald always ops for the most violent solution possible, though is willing to back down if called out on it. Gerald is loyal to no one else but Struthers, anybody else will only receive his aid if they are on his good side, everyone else will probably be the subject of some verbal abuse.
Gerald's knowledge of the world is oddly vast but selective. For example, he isn't entirely familiar with the concept of religion but does know the rules to Volleyball. This might be part of his programming, due to him being designed to be as unhelpful as possible.