Abraham Simpson is the father of Homer Simpson, the grandfather of Bart, Lisa and Maggie, father-in-law to Marge Simpson and the estranged husband to Mona Simpson.
He is often ignored by his family, due to his age and apparent senility, and spends most of his time in the Springfield Retirement Castle. He likes to tell stories which are often highly inaccurate, historically impossible, and/or inconsistent with each other. He has fought in World War II, but it is unsure which of his war stories that are actually correct.
He is voiced by Dan Castellaneta.