Homer Simpson, voiced by Dan Castellaneta, is the patriarch of The Simpsons and is definitely the main character.  Homer is an overweight, slob and a terrible father, but genuinely tries hard.

Homer previously had a job as safety inspector at Mr. Burns' Nuclear Power Plant, but good luck finding out what he's been doing for a living the last few years.

Homer Simpson Quotes

Homer: (Wearing glasses) The sum of the square roots of any two sides of an isosceles triangle is equal to the square root of the remaining side!
Man: (From inside a bathroom stall.) That's a right triangle, you idiot!
Homer: D'oh!

Son, a woman is a lot like a... a refrigerator! They're about six feet tall, 300 pounds. They make ice, and um Oh, wait a minute! Actually, a woman is more like a beer. They smell good, they look good, you'd step over your own mother just to get one! But you can't stop at one, you wanna drink another woman!

Homer

The Simpsons Quotes

Homer: (Wearing glasses) The sum of the square roots of any two sides of an isosceles triangle is equal to the square root of the remaining side!
Man: (From inside a bathroom stall.) That's a right triangle, you idiot!
Homer: D'oh!

Mr. Burns: Oh, and one more thing: you must find the jade monkey before the next full moon.
Smithers Actually sir, we found the jade monkey. It was in your glove compartment.
Mr. Burns: And the road maps, and ice scraper?
Smithers: They were in there too, sir.
Mr. Burns: Excellent! It's all falling into place...