You might never notice him, b... ut then he opens his mouth and he completely creates one character after another.'' Born in 1957, Castellaneta grew up in the small town of Oak Grove, IL, in the northwestern corner of the state, near the Iowa border. As a self-described introvert who developed and honed a facility for slipping into the guise of characters to entertain and make social situations easier (read: class clown), Castellaneta nevertheless diverged from this path in college and worked toward a career as a high-school art teacher via his studies at Northern Illinois University. Then, one of Castellaneta's professors (perhaps sensing some dissatisfaction) wisely admonished him to only work at a field, and in a job, that he loved. Castellaneta reasoned that acting fit the bill, and auditioned for the infamous sketch comedy troupe Second City shortly after graduation. The troupe hired him, and in time, the skills that the actor projected led to his involvement on the then-fledgling Fox network's sketch comedy series The Tracey Ullman Show, which premiered on Sunday, April 5, 1987. Castellaneta joined Ullman, Julie Kavner, Joe Malone, Sam McMurray, and for a time Anna Levine in live-action skits that parodied all aspects of Western culture. As a most unusual aspect of her program, Ullman opted to feature crudely animated, offbeat segments as Monty Python-style transitions between the individual sketches.

The episodes in question were drawn by Gabor Csupo and Groening (at that time, comic-strip artist of growing infamy known for his Life Is Hell series starring a buck-toothed, bug-eyed rabbit named Bucky). Although the subjects of the shorts initially varied, within a few months they began to focus exclusively on a hyper-dysfunctional blue-collar family called the Simpsons; Kavner and Castellaneta voiced parents Homer and Marge Simpson, respectively. Those segments gained such massive popularity that they eventually outshone that of the Ullman show itself (which wrapped in September 1990), and executive producer James L. Brooks, following this cue, decided to spin off the Simpsons into their own weekly animated series. Kavner and Castellaneta, of course, followed Brooks to the new program, joined in time by longtime Brooks acquaintance Harry Shearer, as well as Nancy Cartwright, Yeardley Smith, Hank Azaria, and numerous others. The Simpsons premiered on Fox on December 17, 1989, and became not simply a hit but a phenomenon. It shot up to instantly become one of the highest-rated series on television, and attained iconic status. The program scored as a cause c??l??bre not simply with children (as expected) but with adult viewers as well, who appreciated the show's ability to skewer all aspects of society and culture.

(It generated a billion-dollar marketing boom as well -- an onslaught of Bart Simpson-themed T-shirts, watches, dolls, beach towels, and everything else under the sun.) The program also drew an onslaught of celebrity guests -- everyone from Larry King to Tony Bennett to Beverly D'Angelo and Linda Ronstadt. Castellaneta himself will forever be tied to Homer Simpson -- the lunkheaded, potbellied, beer-swilling, donut-loving nuclear-plant worker with not a whole lot upstairs, and a thoroughly crass lifestyle, but also a big, soft heart (a quality which Castellaneta's co-workers insist that he alone brought to the character). But hardcore Simpsons cultists and even its less attentive devotees will realize that Castellaneta voices not only Homer (as mentioned), but also the gravelly voiced, booze-swilling, womanizing clown Krusty; local drunk Barney Gumble; Scottish elementary-school groundskeeper Willie; the octogenarian family patriarch Grampa Simpson; and innumerable others.

Certainly, it would be difficult to imagine a program that took fuller advantage of Castellaneta's versatility with characterizations. Alongside The Simpsons, Castellaneta has also pursued a career as a live-action film and television performer, and spent most of the late '80s, '90s, and 2000s vacillating between the two mediums. His career on the big screen began at least a year prior to his involvement with Ullman and co., when he debuted with a bit part as Brian in the now-forgotten Garry Marshall dramedy Nothing in Common (1986), starring Jackie Gleason, Tom Hanks, Eva Marie Saint, and Sela Ward. In 1989, Castellaneta landed bit parts in two wildly different films: one as a ma??tre d??? in the Jim Belushi cop comedy K-9, and another (as one of Danny DeVito's clients) in the James L. Brooks-produced jet-black marital farce The War of the Roses. Castellaneta temporarily withdrew from live-action cinematic work in the early '90s, before returning to audiences as the narrator in Super Mario Bros. (1993) and Phil in Warren Beatty's Love Affair (1994). As the Castellaneta's career continued, he then segued into cinematic animated voice-over work (doubtless encouraged by the ongoing success of The Simpsons), doing voices in such features as 2000's Rugrats in Paris (under the aegis of old colleague Gabor Csupo) and Hey Arnold! The Movie (2002). In 2007, Castellaneta extended his Homer characterization to the big screen with his work on The Simpsons Movie -- the first cinematic appearance of Groening's famous animated family. As for television, Castellaneta appeared as a supporting actor in numerous sitcoms during the 1990s. These included ALF (as Steve Michaels in the 1990 episode "Stayin' Alive"), Married...with Children (as Pete in the 1990 episode "The Dance Show"), Wings (as George Wexler in the 1994 episode "Moonlighting"), and Murphy Brown (as Tony Lucchesi in the 1995 episode "Specific Overtures.") He also voiced Genie (inheriting the role from Robin Williams) on the animated Aladdin TV series. Of the Simpsons cast, Castellaneta is one of the only actors to regularly do on-stage comedic improvisation alongside his series work. He is married to Simpsons writer Deb Lacusta, whom he wed in 1987.