NEW YORK - Think of Hugh Laurie in his role as Dr. House. Or William Petersen as Gil Grissom. Or America Ferrera as Ugly Betty.
On the other hand, why think about it? When an actor's perfect in a role it's obvious, so obvious as to feel inevitable, and so inevitable the audience forgets that anybody had to intervene to match the actor with the role in the first place.
Casting is an enterprise whose success is confirmed only in hindsight, once viewers have embraced the casting choice as destiny.
The best casting is invisible. So how hard could it be to pull off?
Turns out it can be tricky. It's a process of discovery mixed with prescience. Gut instinct is important. So is deep knowledge of the churning talent pool. You have to recognize which actor is right for the part. You have to get the actor signed. But first, you have to know the actor exists.
"The key to casting is information," says Marc Hirschfeld. "To be a repository for information: Everything Actors!"
Otherwise? "You'll miss someone."
Hirschfeld is executive vice president of casting for NBC Universal Television, where he oversees casting for the NBC network and other NBC Entertainment programming.
Earlier in his career, he co-founded a company responsible for casting such series as "The Larry Sanders Show," "3rd Rock from the Sun," "Party of Five," and "Seinfeld."
Before that, "Married . . . with Children" was developed for Sam Kinison and Roseanne Barr. But they both passed. Hirschfeld, searching for actors who could save the project, thought of an unknown named Ed O'Neill, whom he'd seen on stage in the decidedly uncomic "Of Mice and Men." O'Neill was perfect as the doltish family man Al Bundy. "Married" became the Fox network's first breakout comedy.
In 1999, Hirschfeld joined NBC Universal, where he describes his job as threefold.
First, to serve as a lookout, "identifying talent I think we should be in business with, and make overall deals with them." (Item: Lauren Graham, perfect for seven seasons on her CW hit "Gilmore Girls," signed a development deal last month.)
He also supervises casting for current shows. (Did you happen to notice Jerry Seinfeld's wildly hyped guest shot on the season premiere of "30 Rock"?)
And he looks ahead to comedy and drama projects in the pipeline, anticipating what their casting needs might be.
"I make lists of names. I'm constantly talking to agents to see who's available, who's not available, who's considering TV this year. Meeting with actors, looking at tapes. Always putting together ideas."
Hirschfeld and his staff of a dozen attend film festivals and comedy clubs, troll the Internet, and even monitor podcasts.
They also draw on a long memory.