Ryan, originally from Rockford, IllInois, was 34 when he went on a few ride-alongs with San Francisco cops and hatched the idea for his own show. He'd previously written for the CBS Don Johnson detective show Nash Bridges (created by Lost's Carlton Cuse) and the Buffy the Vampire Slayer spin-off Angel, but had never worked on the first season of a series, let alone started one from scratch. Initially, he looked at the experience of filming the Shield pilot as a great sample he'd have for his next gig, in part because FX was the channel known for airing Nascar races, not serious scripted fare.

And the most important element of the show, aside from Ryan himself, was the result of a random encounter at a local Gymboree. "My wife dragged me to a Gymboree class for my youngest," recalls Michael Chiklis, like Ryan, an industry lifer, whose role as Vic Mackey on The Shield proved career-making. "We both knew his wife, Cathy, and we were running into Cathy for the first time in over a decade, and she introduces me to her husband."

Cathy then went on to mention that her husband had just sold a pilot to FX called The Barn — the original title of The Shield — and Chiklis asked if he could give it a read. Ryan obliged. "I had no idea that when that script came to my house that it would be a) the best pilot I've ever read, and b) that it would be something that would change my life and career," Chiklis says. Still, it wasn't a simple decision. "Even the people around me were advising against it," he says, "because it was on this cable channel, and I was a network star."

The Shield pilot went on to set a cable series ratings record when it aired in March 2002, pulling in 5 million viewers.

"That morning when the ratings came in, and they were really big, it was stunning to me," says Ryan, his eyes widening. "And I know it was stunning to FX. I know it exceeded their best hopes." He'd gone in assuming he'd never have a second season of the show, but as the ratings and audience continued to grow, it became clear that this was something special.

The Shield went on to win a Golden Globe for Best Drama Series and an AFI award for TV Program of the Year, and it put FX on the map as a network. Even though the show has been off the air for five years, people haven't forgotten about it, especially the executives at FX. In the lobby at FX to this day, one of the first things you see is a giant poster of The Shield, paying homage to the series that changed everything.

"It really was not only the show that launched FX," says FX CEO John Landgraf. "It was the show that launched quality scripted entertainment."

While that is probably something that can be spiritedly debated, the idea that the show fostered an on-set spirit that went on to define an entire network's identity and strategy is clear-cut. "I think one of the reasons the show was so successful is because of how collaborative it was," says Chiklis. "I mean, Shawn was the showrunner, and we gave him that respect. Because at the end of the day, Shawn had the final power. But he was incredibly collaborative, and sensitive, and listened."

Prior to The Shield, Ryan had always been the writer who was planted in the room. Nash Bridges filmed in San Francisco, and writers weren't allowed to go to set. He'd seen a little more when he worked on Angel, but it was limited. So Ryan knew he'd need help when it came to things like casting, editing, and making the day-to-day small decisions that go into production. And he asked for it. Scott Brazil, who had previously worked on Nash Bridges, Hill Street Blues, and JAG, started as The Shield's line producer, and went on to direct and serve as an executive producer.

"We're only paying 85 cents on the dollar compared to network shows to our crew," Ryan remembers telling Brazil. "And I said, 'How are we going to get good crew and keep good crew if we're paying them less?' And Scott's answer was, 'Make it the happiest set on earth.'" Ryan laughs at the conversation since sets are notoriously tough, tougher than being a crooked cop with a captain breathing down your neck. "'Make it a place everybody enjoys coming to work, and everybody feels valued, and that will be worth a 15% premium to people.' And he turned out to be right. The vast majority of our crew stayed all seven years on the show."

Unintentionally, FX was doing something similar with Ryan. The executives realized that since they weren't a big network, they couldn't pay as much. But in exchange, they offered more creative freedom. Unlike the broadcast networks, which were famous for copious notes and edits, FX became a showrunner-friendly environment.

"He has a strong point of view, as you might imagine," Landgraf says of Ryan. "But he's extremely receptive to other points of view, and really wrestles with them when he thinks they have merit… He's a very emotionally mature, sophisticated, and extremely creatively ambitious guy. And those are rare qualities to find in one individual."

And even if Ryan himself doesn't currently have a show on the air, his management style is on display via writers who were part of his process. Former Walking Dead showrunner Glen Mazzara — who Ryan hired for The Shield as a writer and executive producer — thinks of him as a "mentor" from their days on Nash Bridges, and credits working with Ryan for where he is today. "I've tried to pattern the way I run shows and the way I lead writers' rooms [from Ryan] – I really draw a lot of inspiration from Shawn. He doesn't just go with his gut, he thinks about things for a long time. And that can be frustrating to people, particularly working in a creative environment on a show where people need answers and they want to go on. He's willing to say, 'This is my process. It's going to take a while.' But the way he offsets that is he's incredibly funny, he's collegial, he enjoys the process of being in the writers' room."

Even Ryan admits that his favorite part of the showrunner process isn't writing; it's working with the creative people around him. "I've been in many, many writers' rooms with him," Mazzara says. "He puts his head against the window — he likes to have the pane of glass be cool against his bald head. He puts his feet up on the desk, and he usually has some type of Nerf ball in his hand. And he concentrates and everyone stares at him. Then he says, 'I'll tell you what we need to do,' and then he'll pitch the entire story from beginning to end, and that's the story, and he always makes it better."

To people on the Shield set, Ryan was known as Lem, as in Lemonhead, according to Mazzara, "because he was bald." And when faced with the tough situation of long hours on set, he turned to playing online poker to stay awake.

"I was so obsessed with it, at one point during The Shield we used it to name some of the episode titles," he says. That was especially noticeable in Season 3, when back-to-back episodes were titled "All In" and "On Tilt." Ryan says, however, he hasn't played online poker in years.