How Kaley Cuoco Saved The Big Bang Theory From Cancellation

It's hard to imagine "The Big Bang Theory" without its main cast — specifically, Jim Parsons, Johnny Galecki, Simon Helberg, Kunal Nayyar, Mayim Bialik, Melissa Rauch, and, of course, Kaley Cuoco. As the show's original female lead Penny (she's ultimately joined by welcome additions Bernadette Rostenkowski and Amy Farrah Fowler, played by Rauch and Bialik), Cuoco brings a light-hearted and wholly necessary energy to the show — and if you ask people who were there during the inception of "The Big Bang Theory," Cuoco's performance saved the show from a near-certain cancellation.

As former CBS executive Nina Tassler told Emmy Magazine in 2023 (via The Direct), the original, unaired pilot of "The Big Bang Theory," which infamously featured Amanda Walsh as a different female character named Katie, flopped largely because Walsh didn't have good chemistry with Sheldon Cooper and Leonard Hofstadter (Parsons and Galecki, respectively). "There was so much about the pilot that did work," Tassler revealed. "But there were parts of the script that didn't work, and we had to recast an actress [referring to Walsh]. [Chuck Lorre] is such an extraordinary talent. He had a great concept and wonderful chemistry between the two leads, so I asked him if he would try again."

Tassler continued, "And he immediately said, to his credit, 'You're right, I know I can do better. Thank you for this opportunity, and we'll figure it out.'" Tassler credited Cuoco with making sure the series got picked up. "Sure enough, he did. Kaley Cuoco joined the cast, and she was the secret sauce. Chuck and [co-creator] Bill Prady delivered a pilot script, and the rest is history."

A few members of "The Big Bang Theory's" creative team, including casting directors Ken Miller and Nikki Valko and former Warner Bros. executive Peter Roth, told Jessica Radloff in her 2022 book "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series" that once they thought of Kaley Cuoco for the reworked role of Penny, they knew they needed her to get involved in the show. "In hindsight, the role of Katie was an [age] inappropriate role for [Cuoco] in the first pilot," Miller admitted. "But we really believed that she was the one for the second go-around. It was obvious it was her." Roth, for his part, said he put his dignity aside and groveled: "I begged Kaley's team, too. Everything in the second pilot was timed to get Kaley to play Penny because she was exactly what we knew we needed."

Cuoco told Radloff that she initially hesitated, largely because she wasn't really sure what the role of Penny was like and she didn't want to get locked down in a supporting role on a long-running show. Luckily, she decided to say yes. "My team just wanted to make sure I wouldn't be stuck in anything that wasn't an exciting role since it seemed like a secondary character at first, but Nikki and Ken kept saying, 'No, no, it's going to grow! The guys and this new girl are really going to blow each other's worlds up.' And I knew when Chuck [Lorre]'s name is next to something, you really don't question it."

"Kaley's a brilliant comedic actress and as good as anybody I've ever worked with," Roth gushed in the book. "She is going to be one of the biggest stars of all time. So when we got Kaley, that changed everything. She was the catalyst for the success of the show."

Despite Kaley Cuoco's obvious talent — and the fact that changing Katie into Penny and casting her probably ensured that "The Big Bang Theory" moved past the pilot stage — Chuck Lorre admitted in Jessica Radloff's book that the pilot did a major disservice to Penny because it didn't understand her character yet. "One of the most underwritten characters in the show early on was Penny," Lorre said. "It was really obvious immediately that we hadn't developed the character beyond the pretty girl next door, and Kaley was certainly capable of doing a great deal more than what was asked of her. We had to make the character more fully realized. Not just for an episode, but always. [Over time] Penny had an intelligence about people, about relationships, and about sussing out a situation and understanding the dynamics of what's going on in a room."

Meanwhile, it's clear that Cuoco understood Penny right away ... and loved that she approaches Sheldon and Leonard with curiosity rather than contempt. "There's zero judgment from the minute she meets them," Cuoco remarked. "What was interesting was they were judging her. I felt like they were judging her for a long time, and I actually loved that. She just wanted to hang out with them. She immediately included them. But it took them longer to include her." Cuoco is right ... and for many of the show's early episodes, she feels like an audience surrogate as she learns more about Sheldon and Leonard, helping viewers understand these (admittedly weird) guys as she learns more about them.

"Penny found the guys hysterical and cute, but she didn't make fun of them," Peter Roth added, agreeing and pointing out Penny's unexpectedly touching friendship with another series lead. "She thought they were endearing, but never to the point of you feeling like she was secretly mocking them behind their backs. That's why one of the most brilliant relationships was Penny and Sheldon. That was very special."

"The Big Bang Theory" is streaming on Max now.