Caldwell worked as an illustrator for The Charlotte Observer newspaper as well as doing commercial work for an advertising agency, before doing freelance illustrations for magazines such as a series of Barsoom covers for Heavy Metal. He also did cover work for Dragon, published by TSR, publishers of the Dungeons & Dragons role-playing game. “I was offered a job three different times by TSR, Inc., when I was freelancing. Finally, the third time, I decided to come up to Wisconsin to meet the people I was working with long distance, whom I might eventually be working with face-to-face if I accepted the position. I really liked the company and the people, so I agreed that day to work for them.” Some of Caldwell's early work included the covers for the three paintings for the 1985 Greyhawk Adventures novels, and 1985's Dragonlance Calendar, three paintings for the 1986 Amazing Stories Calendar, plus the cover and three interior paintings for the 1987 Dragonlance Legends Calendar, as well as several Dragonlance module covers. He was also known for his work on Star Frontiers. Artist Larry Elmore later commented that Caldwell's dragons, compared to those of other artists, appeared "more serpentine—slimmer and more snakeish."Phillips, Casey (February 19, 2010). "QandA with Larry Elmore", Chattanooga Times Free Press. Distributed through McClatchy-Tribune News Service, February 19, 2010.
