He and his writing partner Joseph Mallozzi wrote lyrics for the Stargate SG-1 title theme and sing them on the Audio Commentary for the season 4 episode "Prodigy".
He became Executive Producer for Stargate SG-1 in season 8.
He became Co-executive Producer for Stargate SG-1 in season 6.
He was a Supervising Producer for Stargate SG-1 in season 4.
He is is often credited alongside Joseph Mallozzi, his writing partner.
He joined the Stargate SG-1 production team at the start of the show's fourth season in 2000.
Paul Mullie: (About the cancellation of Stargate SG-1)I don't really think about the politics and everything, and the money and all that stuff. For me, when a show gets canceled the only question is "Was it done creatively?" And I don't think we were done creatively. That's not necessarily what drives a cancellation in the world of television entertainment. There are a lot of other factors that have to be taken into account. So I don't worry about it in that sense. Hey, stuff happens, right? All I know is that I think the show, ultimately, is still an open-ended concept. That's why Atlantis is still going. That's why Brad Wright and Robert Cooper are working, potentially, on a third series. When you've got a ring that takes you to other planets there's no sealing to that, as far as I'm concerned, not to go on.