Why The Big Bang Theory Ended After Season 12

"The Big Bang Theory" ran for 12 seasons and the same number of years, but even so, when it was announced that season 12 would be the final installment of Chuck Lorre's hit sitcom, fans were stunned — and so were a few of the stars. So why did it end at that point?

The long and short of it, to be frank, is that star Jim Parsons just didn't want to do it anymore. As the Emmy winner told "Doctor Who" veteran David Tennant on Tennant's podcast in late 2020, he felt like he knew the end was approaching when he signed what would eventually become his final contract to play Sheldon Cooper. "Our final contract was for the last two years, but no one knew when we signed it what that would mean," Parsons revealed to Tennant. I kind of had a suspicion in my heart that that was going to be it for me when I did sign that contract, but you never say never and who knows."

Filming a sitcom — particularly one with over 20 episodes per season — is definitely a huge commitment, and as Parsons put it, he was tired, and he was also preparing to lose one of his beloved pets that he shared with husband Todd Spiewak. "I was exhausted, and I was really upset about, more than anything, one of our dogs was getting really at the end of his life around then," Parsons said.

Not only was Jim Parsons understandably exhausted after over a decade of playing Sheldon Cooper on "The Big Bang Theory," but his other professional commitments started to overwhelm him at a certain point. In 2018, a year before "The Big Bang Theory" ended, Parsons joined Andrew Rannells, Matt Bomer, and several other actors in a production of "Boys in the Band" on Broadway, so he ended up splitting his year between the coasts to make it all work.

"It was a complicated road, as you can imagine," Parsons said of the experience. "We went through the 11th season, and then that summer, I went to New York to do 'Boys in the Band' on Broadway, and I think anything I felt [about leaving the show] got really affirmed."

A foot injury that befell Parsons while he was appearing in "Boys in the Band" didn't help matters either; one performance was cancelled, and Parsons' understudy went on for him after that."It was the scariest moment for the next couple of days because I didn't know — I felt like I was at the edge of a cliff, and I was teetering, and I saw something really dark below between the death of the dog, and I don't know what they would have done if I couldn't have gotten back on for the play," Parsons told David Tennant. 

It's perfectly understandable that Parsons elected to leave "The Big Bang Theory" after so long, and it's also understandable that creator and showrunner Chuck Lorre didn't want to continue the series without Sheldon Cooper. In Jessica Radloff's book "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," Parsons' co-star Kaley Cuoco and executive producer Steve Holland revealed that there were definite frustrations over Parsons' decision ... which created major tension on set after the announcement was made.

As Cuoco says in the book, Lorre and Parsons revealed that the latter wasn't going to "continue on," and she actually didn't even fully understand what he could possibly mean. "I was so shocked that I was literally like, 'Continue on with what?' Like, I didn't even know what he was talking about. I looked at Chuck: 'Wow. I thought we were — I'm so blown away right now.'"

Holland also admitted that between Cuoco and Johnny Galecki — who plays Leonard Hofstadter, husband to Cuoco's Penny and best friend to Parsons' Sheldon — there was real frustration regarding Parsons' planned exit (and the end of the show). "At the time, there were a lot of hard feelings between Parsons, and Galecki and Cuoco, who weren't privy to everything that had unfolded leading up to the decision to end the show with season 12, or unaware why they weren't brought into the fold sooner," Holland said. Still, Parsons' co-stars had to understand that the show couldn't go on forever, and all's well that ends well. Plus, Parsons doesn't have to spend his time shouting "Bazinga!" anymore.

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