Working as a casting director can be the most thankless of jobs.

If you’re at the top of your game and cast an untested performer who becomes a star in a film or TV show, it’s the actor and director who get to claim the credit. By contrast, if the actor you cast stinks up the joint, it’s entirely possible that partial blame will—however unfairly—fall on the casting director who brought him or her to the table in the first place.

God forbid that’s ever your fate.

But every once in a while, a casting director can look back on a job well done, having helped launch an unknown talent into the stratosphere, and see their casting instincts rewarded.

Three casting directors were asked to share such stories of discovery and validation. In each case, the casting pro was loath to take much credit, rightly maintaining that such kismet rarely results from a mere single casting decision but is, more often, a cumulative effect.

Jeff Greenberg, Jeff Greenberg Casting (credits include “Cheers,” “Frasier,” “Wings,” “My So-Called Life,” “NewsRadio,” “Ugly Betty,” and “Modern Family,” for which he’s currently on Season 10)

Greenberg—a 14-time Emmy nominee and one-time winner—has been a top casting director for more than 30 years, going back to Season 5 of the classic NBC sitcom “Cheers” in the mid-1980s. He gave early roles to the likes of Kristen Wiig (“I’m With Her”), Millie Bobby Brown (“Modern Family”) and Zooey Deschanel (“Frasier”). And he’d been bringing in Eric Stonestreet to audition for a decade before “Modern Family” came along to pluck the actor from obscurity.

But his most rewarding, memorable and fortuitous casting decision was one he had to fight hard for: Kirstie Alley, when she replaced Shelley Long on “Cheers” in 1987.

Greenberg: “Kirstie came in to audition on a very secret Saturday when the Paramount lot was closed. She read for [co-creators and executive producers] Glen and Les Charles and Jim Burrows. We just wanted to see how the chemistry worked. Then she had to immediately fly to Seattle to star in ‘Shoot to Kill’ with Sidney Poitier.

“Kirstie nailed it, and we told NBC why we wanted to use her. Glen and Les were revered. “Cheers” was one of the network’s premier shows. But the network didn’t know her for her comedy. She was, to that point, primarily a dramatic actress. I had gotten the idea to bring her in from seeing her in “Cat on a Hot Tin Roof,” where Kirstie had generated so many laughs.

“Greenberg’s marching orders had been to find a dark ice queen to replace the beloved Long. Alley fit the bill. But he got consistent blowback from the network.

“At that point, we had to go through this entire exercise of seeing other actors,” Greenberg recalls. “Sharon Stone, Marg Helgenberger and Kim Cattrall were three of them. But we couldn’t find anyone we liked as much as Kirstie. Fortunately, Glen and Les agreed with me, and we were all ready to fall on our sword for her.

“We held out and held out until finally [NBC Entertainment President] Brandon Tartikoff gave in. We won. Then Kirstie distinguished herself at the beginning by not killing it. She was good, but she just wasn’t finding the funny. There was this vague sense of disappointment. The problem was she had such big shoes to fill. Shelley was just so ingenuous as Diane Chambers that negative comparisons were natural.

“Then, maybe seven or eight episodes in, there was this moment when [Alley’s character] Rebecca was supposed to go from her office into the bar during a run-through, and the door wouldn’t open. It was an unplanned thing. The door literally wouldn’t open. And she became this total neurotic mess underneath the veneer of confidence while trying to keep her composure.

“That was the breakthrough. They’d solved he riddle. It was still never smooth sailing. The writers figured out the character along with Kirstie. It was never a slam-dunk. But that was the beginning of a big turnaround.”

Ginny McSwain, GrayKnight Productions (credits include “The Smurfs,” “Richie Rich,” “Garfield and Friends,” “Jimmy Neutron: Boy Genius,” “Darkwing Duck,” “Transformers: Rescue Bots” and “If You Give a Mouse a Cookie.”)

McSwain’s career in casting and directing animation goes back more than 40 years to the age of the iconic Hanna-Barbera Productions and the celebrated director Gordon Hunt. Perhaps her biggest claim to fame was having cast “The Smurfs” in the early eighties, but she also worked with such voice legends as Mel Blanc, Don Messick, Daws Butler and June Foray.

She also had a hand in discovering Nancy Cartwright, who would go on to fame and fortune as the voice of Bart Simpson on “The Simpsons.”

McSwain: “Now let me just say right off the bat that I don’t look at it as making people’s careers like an on-camera casting director might see it. I was more like Santa Claus. I gave them their first job—one that they earned—and then they would do the rest. And as part of that, I brought in this little girl from the Midwest named Nancy Cartwright who got her first leg up in the business with me.

“That was on “The Richie Rich/Scooby-Doo Show” in 1980 and “Richie Rich” in ’82, on which she played the title character’s girlfriend. Then she did the original “My Little Pony” movie for McSwain in ’84, followed by a series in ’86. The following year, in 1987, would come the first “Simpsons” interstitials on “The Tracey Ullman Show” and then the Fox series itself in ’89. Nearly 30 years later, it’s still on the air.

“Again, I don’t go around thinking I made Nancy who she is today,” McSwain stresses. “That said, I’m thrilled that I could help her. She deserves it. She’s a lovely woman, and if I called her tomorrow and asked her for a favor, she’d do it. But she’s done OK, you know? Little did anyone know in 1987 what ‘The Simpsons’ would go on to become.

“Can you even imagine how much these voice actors have made? Oh my God.”

Jodi Rothfield, the Seattle-based Jodi Rothfield Casting (credits include “Sleepless in Seattle,” “Past Midnight,” “Surviving the Game,” “The Ring” and “The Temp.”)

Rothfield has either had a hand in casting or directed the casting for films featuring Tom Hanks, Meg Ryan, Bill Pullman, David Hyde Pierce, Timothy Hutton, Lara Flynn Boyle, Oliver Platt, Faye Dunaway, Rutger Hauer, Natasha Richardson, Charles S. Dutton, Gary Busey. F. Murray Abraham, Helen Shaver and Peter Boyle. Being anchored in Seattle has given her a unique perspective on the film casting world.

For instance, she did some scouting in the early 1990s for the Annex Theatre company, which was co-founded by then-unknown Paul Giamatti and many of his Yale classmates. Giamatti distinguished himself by playing an assortment of eccentrics and psychos in that stage troupe.

Rothfield: “My first feature as a casting director was a theatrical drama called “Past Midnight.” It starred Rutger and Natasha, and I was also casting for a supporting role of a mentally challenged gentleman. Paul got the part. I mean, it wasn’t like I picked him out of nowhere. He was already being recognized at this point as a very good actor. People knew about him. But he certainly wasn’t famous.”

Indeed not. “Past Midnight” is listed on Giamatti’s credits on IMDB as his first feature. One of its associate producers was a man named Quentin Tarantino.

Rothfield recalls, “It’s nice to think I helped put attention on Paul that led to his having this great career. But I think I’d call it a joint discovery. At that time, Seattle had a lot of clout in the business. It was the third largest market. It was L.A., then New York, then Seattle. Portland, Atlanta and Chicago weren’t doing much at that point in the ‘90s.

“For me, the most rewarding thing was having first-time actors come in and being able to groom them. We could encourage them to study and work on their craft, perfecting it. Then maybe a year or two later, they nail the audition because they’re ready. That’s the advantage of being in Seattle. You have casting directors who really love actors, and the actors love coming in to read for them.”

And is that how it happened with Giamatti?

“Oh, no,” Rothfield observes. “I don’t think we had to teach Paul a lot.”