Concept and origins
Groening conceived of the idea for the Simpsons in the lobby of James L. Brooks's office. Brooks had asked Groening to pitch an idea for a series of animated shorts, which Groening initially intended to present as his Life in Hell series. However, when Groening realized that animating Life in Hell would require the rescinding of publication rights for his life's work, he chose another approach and formulated his version of a dysfunctional family. He named the characters after his own family members – his father Homer, his mother Margaret, and his younger sisters Lisa and Maggie. He substituted "Bart", an anagram of "brat", for his own name, and modeled the character after his older brother, Mark.
The five family members were given simple designs so that their facial emotions could easily be changed with almost no effort and so that they would be recognizable in silhouette. Groening submitted only basic sketches to the animators and assumed that the figures would be cleaned-up in production. However, the animators merely re-traced his drawings, which led to the crude appearance of the characters in the initial short episodes. The Simpson family made their debut on April 19, 1987 in The Tracey Ullman Show short "Good Night". In 1989, the shorts were adapted into The Simpsons, a half-hour series airing on the Fox Broadcasting Company. The Simpson family remained the main characters on this new show.
Dan Castellaneta, Julie Kavner, Nancy Cartwright, and Yeardley Smith all began voicing their characters on The Tracey Ullman Show. Nancy Cartwright was the only one of the group who had been trained to be a voice actor while Castellaneta had done some voice over work in Chicago. Castellaneta and Kavner had been part of the regular cast of The Tracey Ullman Show and voices were needed for the shorts, so the producers decided to ask them to voice Homer and Marge rather than hire more actors. The producers decided to hold casting for the roles of Bart and Lisa. Yeardley Smith had initially been asked to audition for the role of Bart, but casting director Bonita Pietila believed her voice was too high. Smith later recalled, "I always sounded too much like a girl. I read two lines as Bart and they said, 'Thanks for coming!'" Smith was given the role of Lisa instead. On March 13, 1987, Nancy Cartwright went in to audition for the role of Lisa. After arriving at the audition, she found that Lisa was simply described as the "middle child" and at the time did not have much personality. Cartwright became more interested in the role of Bart who she found more fascinating because he was described as "devious, underachieving, school-hating, irreverent, [and] clever." Matt Groening let her try out for the part instead, and upon hearing her read, gave her the job on the spot.