An active comics writer with credits for numerous major comics companies DC, Marvel and Image Comics, Seagle has for example written for Superman and Uncanny X-Men, among others. While active throughout the industry, much of Seagle's contributions to mainstream comics over the past decade have come for DC's adult-oriented Veritgo line. For Vertigo, he has produced stories for Sandman Mystery Theater, American Virgin, House of Secrets: Foundation, a supernatural court drama comic, It's a Bird..., a semi-autographical graphic novel that deconstructs the classic Superman myth with artist Teddy Kristiansen, and the supernatural crime series The Crusades, recently reprinted by Image, on which Seagle teamed with fellow Alien/Predator/Aliens vs. Predator contributor Kelley Jones.