Abraham Simpson is estranged husband to Mona Simpson, father to Homer Jay Simpson and Herbert Powell, father-in-law to Marjorie Bouvier Simpson and grandfather to siblings Bartholomew Jo-Jo Simpson, Lisa Marie Simpson and Maggie Simpson.
Abraham Simpson's name derives from Matt Groening's real-life grandfather's first name. However, the writers of The Simpsons TV show were the ones that chose the name not Groening. Also, one of Matt Groening's sons is named Abraham.
Grampa Simpson is an ancient, grizzled and mostly senile figure who lives in the Springfield Retirement Castle, a sad, lonely place filled with demented, crippled, and depressed old people (a sign near the entrance says "Thank you for not mentioning the outside world").
His rambling stories trail away in forgetfulness and despair:
Abe's age is indeterminate, perhaps inconsistent in the series . This includes his being older or younger than fellow cast member Charles Montgomery Burns. He brags that President of the United States Grover Cleveland (March 18, 1837 - June 24, 1908) spanked him on two non-consecutive occasions. He admits to having "taken a shot at Teddy Roosevelt," (October 27, 1858 - January 6, 1919). He is also known to be a decorated veteran of World War II (September 1, 1939 - September 2, 1945) , having somehow earned the Iron Cross during his service in the United States Army— clearing mine-fields. During the same conflict he became a member of the Flying Hellfish Battallion and was placed in command of Charles Montgomery Burns. However, the vast majority of his memories of the past are known to be wildly inaccurate and often physically or historically impossible and thus most likely to be symptoms of his senility.
See: Characters from The Simpsons