He enrolled at the age of ten at the Huntington School of Fine Arts (HSFA), and after high school he attended Alfred University, where he earned a Bachelor of Fine Arts degree cum laude in 1992.
[2] William O'Connor produced interior illustrations for many Dungeons & Dragons books from 1995, and also cover art for the Living Greyhawk Gazetteer (2000).
O'Connor produced a majority of the illustrations for the Star Wars New Essential Guide to Alien Species (2006).
He also wrote instructional art books, such as Dracopedia: A Guide to Drawing the Dragons of the World.
[3] O'Connor was nominated for a Chesley Award in 2002, for Best Gaming-Related Illustration, for Respite card art, "Legend of the Five Rings".