(written from a Production point of view)
Sullivan is a graduate of the University of Southern California Film Writing School, where for a time he also worked as adjunct professor.
He first ventured into television with writing for soap operas As the World Turns and One Life to Live. In 2006, he co-wrote, edited and produced the comedy I'll Believe You. Since then, he has worked as writer and story editor on television series like Criminal Intent, Rizzoli&Isles (featuring Bruce McGill), Revenge, Supergirl and Pure Genius. On the last three, he has also served as a producer.
Sullivan began working as co-executive producer on the series from the episode "Context Is for Kings" and his work in that capacity continues up to the present day. Sullivan also co-wrote the first season episode "Lethe" (with Joe Menosky), and wrote the episode "What's Past Is Prologue", and was interviewed in Episode 7, Episode 10, and Episode 12 of After Trek.
T. Sullivan was named after him.