DuBay had fan art published in many fanzines from 1964. His first professional work was in Charlton's Go-G and Not Brand Echh in 1966 and 1969.

From 1970 until 1983, he was wrote, drew and edited for Warren's Eerie, Creepy, Vampirella, Comix International, 1984, The Rook, The Goblin and The Spirit. He wrote some stories for Heavy Metal and became editor for Archie Comics' superhero line. He wrote and edited features Pacific Comics' anthology Bold Adventure.

By 1984, Stan Lee hired DuBay to set up the animation studios, Marvel Productions. He became head of the Fox Kids department of 20th Century Fox.

With Budd Lewis, he formed Time Castle Books to reprint their character 'The Rook'.