Loeb is primarily known as a comic-book writer, but has also worked on several television shows, including Lost, Smallville, and Heroes. During his tenure at Heroes, he was co-executive producer with Jesse Alexander. After the series went into a creative and ratings slump, both were released from their positions. Loeb is also credited with writing the screenplays for Commando and Teen Wolf.
Loeb’s comic book credits include creating stories featuring Batman and Spider-Man and has worked for both DC Comics and Marvel.