He has written for National Lampoon magazine, The Tonight Show, ALF and The PJs. In 1994, along with Mike Reiss, he created the prime time animated show The Critic, which was cancelled on both ABC and FOX, before finding some success in reruns on Comedy Central. These were also followed by a series of internet only shorts based around the Jay Sherman character in 2001.
He was show runner for Seasons 3 and 4 of The Simpsons, along with Mike Reiss. He was a writer/producer since the beginning of the Simpsons series.
Jean has been prominent in The Simpsons DVD commentaries, being part of the commentaries for almost every episode he executive produced or collaborated on.
Jean is also the creator of the web series "Jesus and His brothers" on Icebox.com.