After graduating from the University of Southern California with a Bachelor of Arts in Cinema-Television/Production, Fullerton worked at Fox Kids Network working her way up to Writer/Producer in the On-Air Promotions department. Her Fox Kids "Bartcasting" campaign, featuring The Simpsons character Bart Simpson taking over the network, won a Promax International Gold Medallion Award. With several of her friends at Fox Kids, Fullerton helped produce the famous Star Wars fan-film, Troops, in which she was credited as post-production supervisor, foley artist, and voice director.

Fullerton has worked in television as a writer and producer, first in promotionals and sales reels, but more recently as a writer and story editor. She wrote several episodes of the first season of Duel Masters, and story-edited and wrote most of the episodes of the second season. Her other television writing credits include Alien Force, Tutenstein, Digimon, Power Rangers Zeo, Zatch Bell, The Super Hero Squad Show and Adventures in Care-a-Lot. She also wrote the fun facts through the Pop-Up Edition of High School Musical and many other Disney Channel Original Movies.

Fullerton wrote four books in the Sonic X series, and wrote the entire Web of Magic series under pseudonym of Rachel Roberts. She has also begun works in comic books and video games, writing the Ben 10: Alien Force segments of the Cartoon Network Action Pack comics for DC Comics and The Warlock Diaries comics for her own Avalon novel series, and stories for several video games in the Ben 10 franchise (including Alien Force, Vilgax Attacks and Cosmic Destruction).