Moore was born in Northampton, England to Sylvia and Ernest Moore. As a child he lived in a lower class neighborhood called the Burroughs although he was often staying with his grandmother, who had no electricity or indoor toilet.
Moore got himself expelled from school in 1970 for distributing LSD, later describing himself as "one of the world's most inept LSD dealers". Later he entered the world of comic books, first trying his hand at being a penciler and then trying out being a writer. Eventually Moore received widespread commercial success for his comic-writing, however he turned his back on mainstream comics to develop other projects.
Moore had two daughters, Amber and Leah with his first wife, Phyllis and for a time they shared their bed with another woman named Deborah. Leah would later become a comic book writer also and marry John Reppion. Much later he married artist Melinda Gebbe.
He is a Neopagan and Occultist whose work has been embraced by numerous counterculture groups.
Alan Moore worked with both of 'The Big Two' and co-created the only graphic novel on Time's 2005 "All-Time 100 Greatest Novels" list, namely "Watchmen". Away from Marvel and DC, he developed "The League of Extraordinary Gentlemen", one of numerous properties started by him of which he disassociated himself from the movie version.
Alan Moore is not given credit as the writer in the Miracleman series and, instead, the credit is given to "The Original Writer" (which is, indeed, Alan Moore). This is due to a legal agreement reached by the two parties.