“Welcome to ‘American Crime.’”

That’s how showrunner John Ridley greeted actor Babou Ceesay on his first day on set. Which would have been fine — except that they were filming “Guerrilla,” the new six-episode limited series Ridley created, wrote, and directed for Showtime (premiering April 16).

“Guerrilla” star Freida Pinto laughs at the memory, which became a running joke for her and her co-star, dismissing it as a rare slip for an otherwise intensely focused filmmaker. “He’s one of the few male multi-­taskers who can give everything its due attention,” she says.

In fact, it had been quite a busy year for Ridley: While “Guerrilla” was under way in London, the third season of ABC’s “American Crime” was in production in Los Angeles. He was also juggling “Let It Fall,” a two-hour documentary about the 25th anniversary of the L.A. riots for ABC News (April 28), and a pilot, “Presence,” that didn’t ultimately get picked up at the Alphabet.

Michael Mueller for Variety

The landscape of television is littered with showrunners juggling multiple projects: Berlanti, Rhimes, Murphy. Joining their ranks was never Ridley’s intention; he seemed firmly entrenched in a career in film after scoring an Oscar for his screenplay for the 2013 movie “12 Years a Slave.” But he’s driven by his passion for the craft of TV. “I really love to write,” he says simply.

But while Ridley is riding the wave, he’s redefining the notion of success in an ever-more competitive business. His uncompromising projects bring prestige and star power — the “Guerrilla” cast also boasts Idris Elba — but not necessarily to millions of viewers.

“If there’s one thing people know about me, it’s that you’re not going to get ratings; you’re not going to make money,” says Ridley. “I hope that I’ve paid back in quality, and being able to at least be part of the conversation. And being part of what people call peak TV.”

When Ridley, 51, first moved into his office on the ABC lot in 2014, he barely had the time or inclination to decorate. Stacks of framed photos and marketing posters lined the floor, waiting to be hung. Three years later, not much has changed. Save for a large black-and-white print of his children, the walls are still pretty spartan. He hardly notices or cares.

“Tell your readers John’s ready to move out in one walk to the car,” he laughs, clad in his uniform of a hoodie, jeans, and knit cap. “I’m still trying to wrap my head around that this is working out at all.”

Patrick Moran, president of ABC Studios, begs to differ. With the three projects across broadcast, cable, and news, Moran says Ridley is the ideal ambassador for the studio. “This is how in a perfect world we’d love our deals to function,” he says, adding, “I don’t know how he juggles it all.”

Says Channing Dungey, president of ABC Entertainment, “There may be a version of the guy who doesn’t sleep.”

Working on three shows simultaneously took its toll, Ridley admits — not just because of the workload, but because of the serious subject matter. While the programs traverse history and cultures and continents, they share a recurring theme — challenging, thought-provoking issues that grab viewers’ attention: Immigration. Sex trafficking. Slavery. Race relations — yesterday and today.

“There are no easy answers in a John Ridley show,” says Moran.

That’s what has the heads of major networks lining up to work with him. Showtime CEO David Nevins calls Ridley “one of the really interesting filmmakers of our time.” Adds Dungey, “He’s one of the great voices of my generation.”

That “American Crime” airs on broadcast is a point of pride for her. In the wake of “12 Years a Slave,” she pursued him aggressively for the network she now presides over.

“As a broadcast network, my main mandate is to do big-tent television that invites in men and women, old and young,” she says. “But secondarily, it’s very important for us to tackle themes and stories that are culturally relevant and have something to say. It’s wonderful when those intersect.”

But ask the filmmaker himself “What defines a John Ridley project?” and he gets thrown. “This is the first time in my life where I can say there are ‘John Ridley shows,’” he says, after a long thoughtful pause. “I’ve never had a space in my life where anybody could ask me that question, or I could even answer that question. I’m at a point where these are the things that I dreamed of. This is a space that’s very rare.”

Michael Mueller for Variety

But as much as he’s eager to drive the conversation, he allows that he ought to also consider letting his hair down. “There are certainly days where I feel like, ‘Hey, I would love to do something that’s entertaining in a different way.’ My kids are like, ‘How come you’re not doing “Transformers”? How come you’re not doing something that’s fun?’” he says.

“I would love to have a franchise. I’d love to have something that earned out. My kids are proud of the things I do, but it’s not like they’re waiting for ‘American Crime’; they’re at that age where they’re waiting for the Marvels and the ‘Star Wars.’ ”

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He may be one of Hollywood’s “big brains,” as Nevins says, but Ridley also has a wicked sense of humor that belies his intensity. He did, after all, get his start doing standup. The evidence is still there on YouTube: The hairline might be a little different, but that verbal patter is familiar, as he riffs on people who smoke while eating, the lack of black serial killers, and, yes, even squeegee men.

Ridley, who grew up in Wisconsin and always aspired to a career in entertainment, translated that comic timing into work in sitcoms like “Martin” and “The Fresh Prince of Bel-Air,” but his industry breakthrough came as a screenwriter, with World War II thriller “Red Tails,” the Jimi Hendrix biopic “All Is by My Side,” and then 2013’s “12 Years a Slave,” for which he also won an Independent Spirit Award, an NAACP Image award, and a Broadcast Film Critics Assn. award.

But before he’d even claimed that Oscar, Moran lured him to ABC with an overall deal (it was extended in 2016 for an additional three years). The two men had first worked together years ago, back at UPN, on a project called “Platinum,” about a family in the hip-hop music industry. “I suspect it was before its time,” jokes Moran, referring to Fox’s megahit “Empire.”

Moran was exploring an idea about a trial of the century that captured the nation’s attention, but Ridley reversed it, making it instead very small — shaping it into what became “American Crime.” Each season of the anthology series examines the impact of a crime on an American town, with many of the actors returning in different roles.

“The show was so incredibly executed in every possible way,” says Moran. “We were thrilled with the outcome.”

In its first two seasons, “Crime” would go on to earn 16 Emmy nominations, including two wins for star Regina King — the first for her role as a devout Muslim woman trying to help her drug addict brother, the second for her turn as the wealthy mother of a high school basketball player accused of sexual assault. (This season she plays a social worker struggling to get pregnant.) But the show didn’t pull in viewers; while season two brought in an average of 3.7 million, season three, which was on the bubble for renewal, bowed to just 2.6 million in its March 12 debut.

“One thing about ‘American Crime’ that I think makes it a successful show — or makes it resonate so much for so many different people — is that as you watch the show, even if it makes you feel uncomfortable, you realize that we’re more alike than we think,” says King. “We all feel guilt.”

Ridley’s commitment to “Guerrilla” pulled him away from the third season of “American Crime.” He’d hoped to direct the first episode — had even written it with that in mind — but he had to turn the reins over to So Yong Kim, who’d been on deck for the second hour. It’s clear the decision still pains him.

“It got to the point where I realized it’s going to be more detrimental [for me to direct],” he says. “I respect the show. I love the show. It was painful because you want to feel like you’re indispensable. But in the end, it was the right move.”

That meant that new cast members like Cherry Jones and Dallas Roberts haven’t ever met the show’s creator.

“That’s what happens when you work with good people. They go off and do other things,” says Felicity Huffman with a laugh.

Ridley was around long enough, though, to give her a few notes on her performance. “Where he basically went, ‘No, that’s not it at all,’” recounts Huffman. “I went, ‘Oh shit.’”

After portraying strong, confident women in the first two outings, this season she plays Jeanette Hesby, a far meeker Southern housewife. Huffman transformed herself physically for the role — gained weight, donned a short, blond wig.

“But you’re still carrying yourself the same way,” Ridley told her. “You come into a room; she slides into a room.”

That note really resonated with the actress, especially having played the same character for eight years on “Desperate Housewives.” “It took me a long time to get to know John,” she says. “I think because he sets the bar so high, I’ve learned not to take my eye off the ball and never take it down.” She’s earned two consecutive Emmy nominations for her work in “American Crime.”

For King, the lessons from working with Ridley have benefited her not just as an actress, but as a director. She learned from watching him how much the environment can help tell the story, which she’s brought into her own behind-the-camera efforts on shows like Fox’s “Pitch” and OWN’s “Greenleaf.”

“That was a nice little jewel to pick up,” she says. “Look, if I could just have a 10th of John’s little secrets and nuggets, I would be OK as a director.”

More than anything, she points to his ability to quietly command respect on the set. “You get more bees with honey,” she says.

Pinto says there should be a camera on Ridley when he’s filming. “He crawls into these tiny spaces so he’s not in our eye line, but so that he can be as close as possible to us,” she says, recounting the experience of filming “Guerrilla.” “This tall man doing this can be quite a sight. He does it so he can communicate with us in a way that doesn’t distract us, but he wants to be up close to the action.”

Michael Mueller for Variety

“Guerrilla” has long been a passion project of Ridley’s. The swirl of headlines about Donald DeFreeze, the kidnapped Patty Hearst, and the Symbionese Liberation Army back in the 1960s seized his young imagination and never let go. “These are the baddest motherfuckers on the planet,” he remembers thinking.

As he got older, he realized the situation was far more complex — but he still couldn’t let go of the idea of a couple who wanted to get involved and “got to the point where they think they can only affect change through the barrel of a gun.” In 2007, faced with what he calls his own existential crisis, he happened to meet with Patrick Spence and Katie Swinden, execs at the production company Fifty Fathoms, who asked him the question all filmmakers want to hear: “If you could do anything, what would you do?”

After some research into the Black Power movement in the U.K., that revolution story became “Guerrilla.” Ridley transplanted the action to 1970s London, and pitted fictional young activist/lovers (Pinto and Ceesay) against Scotland Yard’s Black Power Desk, which was dedicated to thwarting the movement.

“You go to this space from people being baffled by your ideas to a lot of folks going, ‘This is necessary,’” recalls Ridley. Elba signed on not only as an executive producer to help get the project off the ground, but agreed to star in it as well, though in a less showy role — that of Kent, a mentor to the couple. (“Guerrilla” ultimately landed at Sky Atlantic as a co-production from ABC Signature and Fifty Fathoms.)

Though the series’ roots may be quintessentially British, its themes are universal, and particularly timely.

“The race issues that are going on in the States at the moment are so real and so current that in a way it’s easier to tell a story about their history by looking at another country than it is by doing something on the nose,” says Swinden.

When Sky Atlantic brought in ABC Signature as a U.S. partner (the show will air simultaneously in the U.K.), the pitch made the rounds — but Nevins called Moran daily to make sure he landed it as the first of the cabler’s upcoming lineup of limited series (along with David Lynch’s “Twin Peaks” and “Purity,” starring Daniel Craig).

“It’s a very old story that has real contemporary resonance,” says Nevins. “Ridley’s got something he wants to say, and he makes you want to pay attention.”

Ridley admits he was a bit intimidated by having to direct Elba. But he realized fawning over his star wasn’t going to be conducive to a day’s work. So he “put his game face on” and stepped in.

Elba, who calls Ridley’s writing amazing, says he signed on for the experience of working with him. “I thought I could learn something from him and I did,” he says. “I learned that the difference between a good story and a bad story is how you tell it.”

Although he was concerned about the number of projects on Ridley’s plate, Nevins couldn’t be more pleased with the final result. “I think it has this great, rebel badass-ness to it, which I was always hoping it would. It’s got characters with real swagger,” he says. “It’s engaging and it’s politically moving, but it’s also really fun.”

When ABC News asked Ridley if he’d be interested in directing a documentary about the 25th anniversary of the L.A. riots, his team jumped in to say he was too busy — but Ridley himself couldn’t pass up the opportunity. For him, it’s a project a decade in the making. That is, he’d already done the homework: He’d written a narrative feature that Spike Lee was going to direct, and Brian Grazer and Ron Howard were going to produce.

“I always loved that story, but I just assumed at some point, ‘This is not going to get made,’” he says. (The Grazer/Howard project is still in development, looking for financing.)

But, aided by executive producer Jeanmarie Condon, he found the time to do the interviews for the ABC documentary, called “Let It Fall,” which will get a limited theatrical release to qualify for Oscar consideration.

Michael Mueller for Variety

“This is not talking heads. This is not historians. This is not people three steps removed,” he says. “These were folks who were there.”

“Let It Fall,” which Ridley wrote, directed, and produced in partnership with Lincoln Square Productions, takes an unflinching look at the decade surrounding the event that led up to the uprising, as he calls it, recounting the events throughout the city from the perspective of a range of voices — black, white, Hispanic, Korean, and Japanese-American. His only regret is that the police officers involved in the Rodney King beating declined to be interviewed.

“It was not my desire to indict, and it was not my desire to exonerate,” he says. “I feel like it was a missed opportunity to complete a story.”

What he learned, he says, is that “people have a choice. We can be the best of ourselves, we can be the worst of ourselves. That best or that worst, it is not defined by race or ethnicity.”

Ridley may finally be due a break, but that’s just not in his DNA.

“I’m in that sort of semi-antsy spot right now,” he says. Ever restless, he’s already sent several ideas to Moran: a script he wrote in his “spare time,” and a pitch for a comedy. And a long-rumored, mysterious Marvel TV project is yet alive, shrouded in as much secrecy as ever.

“I still want to do it. Hopefully it will still get done,” he says, adding with a laugh, “They’ve got a release schedule that far exceeds my life expectancy.”

He’s also developing a script for FX with King — who has her own development deal at ABC — about the Atlanta child murders in the late 1970s and early ’80s.

“It’s about a horrific piece of history,” he says. “It ain’t broadcast television. Just because of Regina, it’s going to be terrific, but it’s going to be challenging.”

On top of that, he’s writing another project on spec for King to star in, with the intention of taking it out to buyers later this year.

And he can expect to hear from Nevins — that is, once he turns in that final episode of “Guerrilla.”

“I feel like this is a guy I plan to work with for the rest of my career,” says Nevins. “He’s going to be a major force for the next 25 years. No question about it. I definitely want Showtime to be at least one of his homes.”

And Ridley would love to return to the feature world, but he is wary of being pigeonholed.

“You do things like ‘Red Tails,’ or ‘12 Years,’ or even Hendrix, and people think, ‘Oh, if we’re going to do a historical or biographical piece about people of color, who better than John?’ I get a lot of calls for those kinds of films,” he adds with a sigh.

Should ABC renew “American Crime” for a fourth season, he’s already got an idea for what themes it would explore, as with “Guerrilla.” But he’s got one note, and it’s about scheduling.

“I’d love to come back and do more projects,” he says with a laugh. “We just need to need to separate them.”

Leo Barraclough contributed to this report.