Forbeck first became interested in role-playing games at age 13 when he started playing Dungeons & Dragons. He earned a degree in creative writing from the Residential College at the University of Michigan and graduated in 1989. Forbeck began working full-time on games and fiction after graduating. He was the editor on an adventure by Gary Gygax for New Infinities called Epic of Yarth: Necropolis. He wrote Outlaw (1991) and Western Hero (1991) for the Iron Crown Enterprises and Hero Games. Forbeck and Shane Hensley formed Pinnacle Entertainment Group to publish Deadlands. Forbeck spent four years as the president of Pinnacle and was the director of the adventure games division at Human Head Studios for two years. Forbeck left Pinnacle to move to Alderac Entertainment Group just before the two companies ended their relationship, and sold his Brave New World role-playing game to AEG. Forbeck has designed collectible card games, roleplaying games, miniatures games, and board games, and he has written short fiction, comic books, and novels for the companies Wizards of the Coast, Games Workshop, TSR, Decipher, White Wolf, Pinnacle, Green Ronin, AEG, Reaper Miniatures, Image Comics, WildStorm Productions, Idea + Design Works, and many others. Forbeck has also worked for Atari, Ubisoft, Mattel, Playmates Toys, and Human Head Studios. Along with game designer Jason Blair, he wrote the script for the video game Conduit 2.
Forbeck has won Origins Awards for Best Roleplaying Game for Deadlands and The Lord of the Rings Roleplaying Game, Best Miniatures Rules for Warzone and The Great Rail Wars, Best Roleplaying Adventure for Independence Day, Best Fantasy Board Game for Genestealer, and Best Short Story for "Prometheus Unwound" from The Book of All Flesh. He is the author of the well-received Secret of the Spiritkeeper, the first book in the Knights of the Silver Dragon series.