The Big Bang Theory's 200th episode: How the CBS series made it this far

The Big Bang Theory may be America’s No. 1 comedy now, but CBS’ geeky sitcom about a quartet of comic book-obsessed scientists and their out-of-their-league neighbor once struggled to get off the ground.

The series, created by Chuck Lorre and Bill Prady, debuted in 2007 to roughly 9.5 million viewers — certainly not ratings to balk at now, but the writers’ strike would prove to be an obstacle just a month after the show bowed. “We did seven or eight episodes and then the writers’ strike hit,” star Johnny Galecki tells EW. “We had a lot of things that were stacked against us. I know everyone feels like their show is the little show that could, but I feel like we really overcame a lot.”

However, the writers’ strike may have been a blessing in disguise. “I always actually point to the first season with the writers’ strike, when the eight episodes that we made were re-running and CBS said they’re kind of going up in the numbers,” Prady says. “I said, ‘All right, maybe this is something.’ ”

Part of the appeal of The Big Bang Theory, many say, was the notion that the leading characters — played by Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, and Kunal Nayyar — were the underdogs. “In the DNA of the show is people on the outside wanting to fit in,” executive producer Steve Molaro says. “If you’re a nerd or a cool kid, it seems like it’s a global feeling that this show has managed to tap into. Who would’ve thought it would have this kind of lasting power. We’re still amazed by everything that’s been happening.”

The Big Bang Theory also did what many shows probably wouldn’t dream of doing now by really taking its time to delve into storylines, sometimes moving at a glacial pace. Sheldon and Amy’s (Mayim Bialik) relationship is a prime example: Only now, in season 9, have they finally slept together for the first time. “The key element is the writers’ devotion to those characters, and the ability and determinedness not to change them in ways that alienate viewers,” Parsons says. “We’re not a procedural, there’s no mystery being solved here, there’s no crime being revealed. It’s simply a matter of, ‘Do you want to tune in and watch these people deal with this s— or not?’ “

That’s not to say the actors weren’t champing at the bit for more in the beginning, though. “We talked early about these characters growing, evolving, maturing at the pace of molasses basically,” Galecki says. “The cast, we were all so excited to play these roles. Selfishly, as an actor, you want to take that ball and run with it immediately, and explore that character in a million different settings, scenarios and situations. Chuck was like, ‘It’s best to be patient with it.’ There have been leaps of evolution and maturity based on things that have happened in their lives just to stay responsible to how human beings react to falling in love, having their heart broken, whatever the case might be. Otherwise, it’s been slow and it’s great. It keeps the characters relatable and recognizable, [and] friends and family to the audience.”

And that’s exactly what was key to the show’s success, according to Lorre. “It’s the kind of family you want to be a part of, the way you wanted to sit at the bar at Cheers and have a drink with Norm and Cliff and talk to Sam,” he says. “I think that surrogate family quality is magical and mysterious. It’s definitely happening with these guys.”

If you ask the cast, that familial feeling comes down to what the brain trust behind Big Bang have created. “It’s the writing,” Nayyar says. “The quality of writing has been so good for so many years; in fact I think this is our strongest year yet, to be honest.”

On the flip side, the executive producers feel the same way about their stars. “Obviously a very big part is this amazing cast, all seven of them, incredible actors, incredibly appealing. Pick any two of them, put them in a scene and it’s already halfway to being great and I haven’t even typed a word yet,” says Molaro, who points to the development of the Penny character as a real turning point for the show in its early stages. “I think her character wasn’t as quite fully realized [as the rest] of them early on,” he says. “When she started to come into her own, and you could see she really loved them, but she wasn’t afraid to stand up to Sheldon, that’s when I feel we started to click into a groove and we started to hit some of those early classic Sheldon-Penny scenes, which we’re doing to this day. There’s a beautiful Sheldon-Penny scene in the 200th episode.”

Not to sell the men short, by any means, but the introduction of Bialik and Melissa Rauch in season 3 added a whole new dimension to the series. “The show has been able to grow as we added Mayim and Melissa and those relationships have expanded what the show’s about and the kind of stories we can tell,” Lorre says.

“I think it opened up a lot of plot points,” Bialik concurs. “I don’t want to take credit for that. It just made the show a lot more relationship-friendly in terms of doing a lot more scenes and plot lines about relationships.” Adds Rauch: “I was such a fan before I joined the cast, so for me, I thought it was special and the chemistry was just out of this world out of the gate. I feel like we just got to join an already incredible, well-established, amazing group of people who had these amazing group of writers writing for them.”

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Soon the comedy went from the little show that could into an unstoppable juggernaut. “When we first premiered, the ratings we had were very healthy — they’d be very good in today’s market,” Parsons says. “Before we aired, we had done four or five shows, and I knew that we were doing good work, and I knew also that there was no way to know what other people were going to think of it. I had watched too many wonderfully done shows go off the air after seven episodes or one season. You just can’t know.”

It was when the show hit a landmark number in its second season that it started to feel real for the cast. “That’s really the audience gathering around and telling their friends and family,” Galecki says. “That’s really due to the [fans]. But I remember the first morning we learned we had 10 million viewers the night before, we all knew we’d have a job at least for the rest of the year.”

Word of mouth was vital for The Big Bang Theory, which became evident on their inaugural trip to Comic-Con in the summer after their first season. “We were not, by any stretch of the imagination, a hit show,” Lorre says. “We went to Comic-Con and there were 4,000 people in the room going crazy when they saw the cast come out. I went, ‘Okay, something’s happening. This is so unanticipated. Something’s happening here that’s remarkable and we never saw it coming.'”

Going into season 3, The Big Bang Theory then moved behind Two and a Half Men on the schedule. “Everything exploded,” Parsons says. “The great thing was is we had those two years before us under our belt. We had a foundation under our feet. So when the ratings got so much higher, it was only a time to rejoice. It wasn’t freaky in any way, because it didn’t change the show. The show was already the show, we just had the chance to expose it to more eyeballs.”

It also helped immensely when The Big Bang Theory began airing in syndication in the fall of 2011, coinciding with the debut of season 4. “When we went into syndication when it started airing on TBS, that’s when life really changed, because that’s when our ratings went nuts,” Nayyar says. “That’s when it was on the air 10 hours a day and people started recognizing us on the street. That’s when life became different.”

Even with the show’s success, some of the cast were still pinching themselves. “I still don’t know where the turning point is,” Cuoco says. “I still think we’re struggling. I still think this show is teetering. I have to live like that because if I just settle in and pretend everything’s great, it’ll mess my mind up. I still hope people will watch the next episode.”

“Even when we got picked up for two seasons simultaneously, which is very rare, there were other shows that Chuck was involved with that were having various states of drama and implosion,” Helberg says. “You never know. You just never know ever. Honestly, the last couple years I felt like, ‘Okay, I should hang a picture on my dressing room wall. I think I can put a nail in there and feel confident I’ll be here tomorrow.’ It was always a reasonable or healthy amount of skepticism. We really enjoy the hell out of it. We’re not tired of it.”

That, paired with the aforementioned lack of controversy on their own set, is what ultimately kept the show alive, Prady says. “The only thing I can point to is that it’s still very fun to make,” he says. “When something is fun to make, I think that shows in the final product. When things stop being fun to make, when it’s a grind, I think what you make feels like a grind. We still like each other and it’s still fun to make.”

The Big Bang Theory airs Thursdays at 8 p.m. ET on CBS.