There are many fathers on The Simpsons including:
Apu Nahasapeemapetilon
Homer Jay Simpson
Ned Flanders
Apu
His full name is Gil Gunderson as can be read on the simpsons character list on wikipedia...
His father's name was David Simpson
Erin Hardnipples Simpson
His full name is Carl Carlson.
His full name is Marion Anthony 'Fat Tony' D'Amico.
His full name is Waylon Smithers, Jr.
Homers father is most commonly referred to as "Grandpa" on the Simpsons. Nearly all of the Simpsons clan refers to him as this. His actual name is Abraham Simpson, or "Abe" for short.
Thomas Bradley Simpson.
i think hat his his name because that's waht wikipedia says
His full name is Francisco Dominguez.
that is his full name, but throughout the book he is called "father"