He has regularly written and produced American television programmes since his initial job as one of the key above the line crew members on most of the run of The X-Files and its spin-off, The Lone Gunmen. Indeed, his work on The X-Files twice earned him an Emmy Award nomination, one for producing and one for writing.
Following the demise of both those shows, he joined the writer's room on Star Trek: Enterprise for its second season, on which he was also a co-executive producer. He notably wrote the episode Canamar, which featured Emmy Award-nominated make-up by future Miracle Day make-up head, Todd McIntosh. This association with Enterprise allows him to join Jane Espenson as one of only two people to write for both the Star Trek and the Doctor Who franchises on television.
From Enterprise, he moved on to the short-lived Threat Matrix, and then to a much longer association with the show Supernatural, where he held several titles and wrote several episodes across the first three years of that show's run. He then moved over to Legend of the Seeker for a year before landing on his next major project, Breaking Bad, for which he has been thrice-nominated for a Writers Guild of America Award. Just prior to working on Torchwood, he worked on The Vampire Diaries.