What is the meaning of the title, Jimmy Corrigan: smartest kid on Earth? This has been mentioned before, but so far there hasn’t been a definite answer.
Jimmy’s childhood is rarely mentioned, so we can’t really know if he was a smart kid. As an adult, he doesn’t seem very bright. At the beginning of the book, a man in a superhero costume tells Jimmy’s mother that Jimmy is a very smart kid. However, the man didn’t mean it and seems to be trying to find a way to talk to Jimmy’s mom. In this event, by being quiet Jimmy was rewarded, in contrast to his later life where his silence just makes the situation awkward.
So we can assume that Jimmy wasn’t the smartest kid, and that Ware was being sarcastic when he chose the title. In fact, other parts of the title are also misleading. Much of the story is about Jimmy as an adult, instead of a kid. The title could refer to Jimmy’s grandfather, James Corrigan, but James doesn’t fit the title of being the smartest kid on Earth either.
The part of the title about being on Earth could also be a falsehood. Jimmy spends an incredible amount of time daydreaming, so it doesn’t always seem that he really is on Earth.
I think that Ware chose the title sarcastically, to enforce the generally theme of Jimmy’s depressing life. It could have been that he intended to write a story about a smart kid, since at the end he mentioned that he didn’t really have a plot lined out for the story, but I think that is unlikely.