The Law & Order series is one of the most successful franchises on television, so much so it even spawned a few successful spin-offs. Despite its success, however, the Castle creator was unimpressed with the series’ quality. And he set out to make a show that had everything he believed Law & Order didn’t.

‘Castle’ creator Andrew Marlowe felt ‘Law & Order’ was very dry

Castle creator Andrew Marlowe was already a successful screenwriter before creating his hit television series. He wrote films like Air Force One and End of Days. But it was his experience with writing films that made him want to tackle doing a television series instead.

“Well, I was primarily a feature writer, and I was stuck in my ten-by-ten room, and I thought, wouldn’t it be great to get out of the room and actually do some of the things I was writing about? Just translating that notion to Castle seemed relatively friendly,” Marlowe once told Assignment X. “What is it like to have a writer who has all this book information actually have to go out into the real world? There is also a part of me where I love the old murder mysteries.”

But Marlowe didn’t want Castle to be like the procedurals he saw on modern television. To him, these shows didn’t have enough focus on character, which he hoped to remedy with his own project.

“The recent procedurals like CSI and Law & Order are a little too dry for me, because it doesn’t really focus on the character, it focuses on the minutia of the law or the minutia of the evidence that I like to call ‘evidence porn,’ because they show it in beautiful light to the music montage,” Marlowe said. “What I was missing were the characters that I loved growing up on the shows like Rockford and Columbo, Moonlighting, all those great mysteries.”

“So between me wanting to get out in the world and do stuff and projecting that onto Castle and wanting to be part of a show that had great characters that felt like the shows that I loved growing up, I just came up with this idea,” he added.

Similarly, one of the reasons why Fillion was drawn to Castle was because of its humor. The Rookie star felt his show’s lighthearted nature was a stark contrast to more serious shows like Law & Order.

“If people are like me and watch a crime drama, and they say, oh that would have been a really good joke there if he only went for it,” Fillion once told My Take On TV. “There was a call back, all you have to do is say that would have been a good joke. On Castle, we go for it. The humor in life. On Castle, we try to find the life. We’re not all dark, driven, and haunted. It’s people doing their job, going out there. There’s comedy in life. On Castle, we find it.”

Andrew Marlowe felt Nathan Fillion’s ‘Firefly’ connection helped ‘Castle’

Although he crafted the character, Marlowe felt Fillion’s performance had a huge influence on the role. He credited Fillion for a lot of the show’s humor.

“Nathan’s brought Castle to life in such a unique and specific way that it all has to be filtered through that brand of humor, that irreverent attitude, and to be able to play it with charm, given that we’re dealing with dead bodies, so he doesn’t come across as being insensitive. And I think that Nathan’s really able to walk that fine line, and we’re able to write to it,” Marlowe said about Fillion.

But Marlowe also believed that Fillion’s Firefly roots played another part in Castle‘s overall success. Fillion might’ve cultivated such a devoted fanbase with the sci-fi series, that they followed the actor on his Castle journey.

 “I think that they’ve been very helpful,” Marlowe said. “His Firefly fans are very devoted to him and we appreciate being able to share the same universe as them.”

It helped that Castle featured quite a few references to Firefly. There was one Halloween-themed Castle episode where Fillion even dressed up as his Firefly counterpart Malcolm Reynolds.

“It was actually the writer of the episode, Terry Miller, who brought the idea to us, because it was a Halloween episode and she felt it would be a natural way to honor Nathan’s fans,” Marlowe remembered. “And we took it and ran with it, and Nathan was very excited, I was very excited by it, but that came from one of our writers [saying], ‘You know what would be cool?’”