Elfman is one of the most prolific and accomplished composers for film and television, creating music for 16 movies by Tim Burton, including "The Nightmare Before Christmas" and "Batman," as well as the scores for the three "Men in Black" films and the theme songs to "Tales from the Crypt" and "The Simpsons."
"The Simpsons" theme song made him lots of money, as to be expected. "Those are the three notes that kept me in health insurance for 25 years," Elfman told Classic FM, likely meaning the song kept him in the Writer's Guild so he could keep his health insurance while working on other projects. "It was such a weird show. I thought it was going to run two or three times and disappear forever."
Elfman wrote the theme song in "in one day … in the car on the way home from the meeting, and ran downstairs to my studio, recorded a demo, sent it out. That's exactly what plays at the beginning of 'The Simpsons.'"