His work includes 9-1-1: Lone Star, CSI: NY, Rush Hour, Revolution, Station 19, and Supernatural, for which he created the popular recurring characters known as the Ghostfacers.

He has penned original pilots for multiple American entertainment companies including Netflix, Amazon Studios, CBS, ABC, the CW, Turner Network Television, Showtime Network, A&E, and The Disney Channel.

Callaway was the executive producer and co-showrunner of the Fox Television crime procedural APB and was the showrunner of The CW drama The Messengers.

He co-created and executive produced the science fiction television series Mercy Point on the UPN network.

Callaway is also a professor in the USC School of Cinematic Arts at the University of Southern California.