Hamill is the co-writer of "The Black Pearl", a comic book miniseries published by Dark Horse Comics. He wrote an introduction to the Trade Paperback "Batman: Riddler Two-Face" which reprints various stories involving The Riddler and Two-Face to tie in with "Batman Forever". He has also written several stories for "Simpsons Comics", including "Catastrophe in Substitute Springfields!", which parodies DC's "Crisis on Infinite Earths" and also references several other classic comics.