From 1991 to 1993, O'Brien was a writer and producer for "The Simpsons". When O'Brien first arrived at the Fox lot, they temporarily gave him writer Jeff Martin's office. O'Brien was nervous and self-conscious, feeling that he would embarrass himself in front of what he regarded as an intimidating collection of writers. O'Brien would pitch characters in their voices, as he thought that was the norm, until Reiss informed him that no one did this. He fit in quickly, commanding control of the room frequently; writer Josh Weinstein called it a "ten-hour Conan show, nonstop". According to John Ortved, one of his fellow writers said that Conan had been a shoo-in to take over as showrunner.