Groening's father's name was Homer, his mom's name is Margaret, and his sisters are named Lisa and Maggie.
He started "The Simpsons" by making animated shorts for "The Tracey Ullman Show". He didn't want to adapt his comic series "Life in Hell" for the cartoon, so he made the show about a dysfunctional family instead.
Because he didn't want the show to be autobiographical, he named the older brother character "Bart" instead of Matt. Why Bart? Bart is an anagram for "brat".
(Sources: 1, 2)