Describe Homer Simpson here
You mean Dan Castellaneta, his voice actor?
D'OH!! Okay, lemme repeat...
Daniel Louis "Dan" Castellaneta (born October 29, 1957) is an American film, theatre and television actor, comedian, voice artist and television writer. Noted for his long-running role as Homer Simpson on the animated television series The Simpsons, he also voices many other characters on The Simpsons, including Homer's senile father Abraham "Grampa" Simpson, town drunk Barney Gumble (though he did sober up in the later episodes and now isn't seen as much), Depraved Kids' Show Host Krusty the Clown, angry Scottish school janitor Groundskeeper Willie, the John F Kennedy-esque Mayor Quimby (complete with Boston accent, a large political family mired in sexual scandal and general debauchery, and chasing skirts behind his Jackie O-looking wife's back), unlucky helicopter reporter Arnie Pie, Jeremy Freedman (formerly named "The Squeaky Voiced Teen"; a teenaged boy who can be seen slaving away at Krusty Burger, the local supermarket, the movie theater, and Phineas Q. Butterfat's ice cream parlor), Chespirito (the excitable, Spanish-speaking actor in a bumblebee costume who had his own sitcom -- hasn't been seen much after season twelve), and (allegedly) elderly Butt Monkey Hans Moleman. Castellaneta is also the voice of the titular character in Earthworm Jim, Megavolt in Darkwing Duck, the Robot Devil from Futurama, The Ventriloquist and Scarface in The Batman and the second voice of Genie from Aladdin, replacing Robin Williams.
Born in the Chicago suburb of Oak Park, Illinois, Castellaneta started taking acting classes at a young age. He would listen to his father's comedy records and do impressions of the artists. After graduating from Northern Illinois University, Castellaneta joined Chicago's Second City in 1983, and performed with the troupe until 1987. He was cast in The Tracey Ullman Show, which debuted in 1987. The Tracey Ullman Show included a series of animated shorts about a dysfunctional family. Voices were needed for the shorts, so the producers decided to ask Castellaneta to voice Homer. His voice for the character started out as a loose impression of Walter Matthau, but later evolved into a more robust voice. The shorts would eventually be spun off into The Simpsons. Castellaneta has won four Primetime Emmy Awards for Outstanding Voice-Over Performance for his work on the show as well as an Annie Award for Outstanding Individual Achievement in the Field of Animation in 1993. Castellaneta has co-written four episodes of The Simpsons with his wife Deb Lacusta (season 11's "Days of Wine and D'oh-ses," season thirteen's Clip Show episode "Gump Roast," season fifteen's "The Ziff Who Came to Dinner," season 17's "Kiss Kiss Bang Bangalore" and season 22's Christmas vignette episode "The Fight Before Christmas").
Castellaneta has also appeared on some live-action TV shows and movies, such as Arrested Development (as a doctor who used Homer's "D'oh!" catchphrase when a surgical procedure went wrong), Married... with Children (as a gay man who stays with Al after finding out that his husband has been dancing with Al's wife Peg in one episode and a casket salesman in another episode), Castle (as Rick Castle's judge friend), Reba (as Reba's boss who was fighting with her ex-husband over Barbra Jean), How I Met Your Mother (a local homeless man who steals Marshall's charts), The Pursuit of Happyness (as the boss of a stock firm), and Space Jam (as a random man at a basketball game).
It should be noted that, unlike the famous character he voices (Homer Simpson), Dan Castellaneta is actually a vegetarian, a teetotaler and practices tai chi.