John Miller joined Tri-Star Pictures in 1985 as the story department assistant, processing the thousands of submissions the studio received each year, while moonlighting as a freelance script analyst for producers such as Jim Brubaker, Fonda Films and White Eagle Entertainment. After a series of promotions, he became the Literary Editor in 1993, managing the story department library, supervising and training script analysts, and acting as the liaison with the New York publishing world, placing novelizations with publishers and looking for novel-based film projects. John put projects into development based on the novels Rune and Cage, and on the short story "The 730 Club".

John moved to Seattle in 1993 where he was the director of development for ShadowCatcher Entertainment and has taught a class at the University of Washington's Experimental College called "Selling your Screenplay to Hollywood".