The first scene of “Other Space,” a new sci-fi sitcom by Paul Feig, which streams on Yahoo on April 14th, begins with one of the show’s central characters, a hapless spaceship captain named Stewart Lipinski, navigating the ship through an asteroid shower while eating a hot dog. On a Saturday last August, however, on the first day of casting, the script was in flux and the hot dog was still written as a banana. Allison Jones, the casting director, was reading the scene with actors trying out for the Stewart role, who faced a decision: audition with a real banana, or just pretend to eat one?

Jones works out of a bungalow in the quaint Larchmont neighborhood of Los Angeles. The rooms of the house are airy and filled with mementos of her thirty-year-long career in Hollywood: bobble-heads of characters from “The Office,” which Jones cast; a bulletin board collaged with head shots. In the waiting room, next to the sign-in sheet, a bowl of candies and bubble gum greets nervous actors. The audition room is austere, with no windows and just two chairs. Jones hates asking her staff to work on weekends—“They don’t make enough money,” she said—so she was alone, with a video camera mounted on a tripod, reading lines as one aspiring Stewart after another passed through, four minutes apart. Most of the actors pretended to eat a banana, but some had brought in a real one, which suggested to Jones that they were trying a little too hard. Early in the day, a young man came in wearing suspenders over a Stanford T-shirt and with military ribbons taped to his chest. When he pulled a banana out of his pocket, Jones quietly sighed. A few moments later, it popped out of its peel and landed at Jones’s feet. This was nothing, she later told me; once, during an emotional table read, an actress accidentally punched her in the face.

In the early days of Hollywood, casting directors had little decision-making power. Most working actors were signed to individual studios, and casting mainly involved matching individuals to roles based on the actor’s availability and type. In the nineteen-sixties, as the studio system broke down, the influence of casting directors grew. Heavyweights like Marion Dougherty discovered young talent on Broadway and persuaded directors to hire such unknowns as Al Pacino, Paul Newman, and Robert Duvall. Jones began her career with the two-beats-and-a-punch-line sitcoms of the nineteen-eighties, but, in working with Feig and the director Judd Apatow, she was required to try something revolutionary: find comedic actors who, more than just delivering jokes, could improvise and riff on their lines, creating something altogether different from what was on the page.

In the process, Jones has helped give rise to a new kind of American comedy. In 1999, she cast Seth Rogen, James Franco, and Jason Segel in the critically acclaimed, poorly watched teen series “Freaks and Geeks.” The show, created and written by Feig and produced by Apatow, was a coming-of-age story set in the suburban Michigan of Feig’s youth. Jones won the show’s only Emmy, for her casting. Several years later, she met with a young, sweaty Jonah Hill, who was desperate for an introduction to Apatow. She told Apatow that Hill was weird and hilarious. That sufficed; Apatow expanded a cameo part for Hill in “The 40-Year-Old Virgin,” as an odd but lovable eBay customer. Two years later, Hill was cast with Michael Cera in “Superbad,” a raunchy teen comedy that Apatow produced. It was left to Jones to find their nerdier-than-thou friend McLovin. Jones posted notices seeking high-school students in L.A. After seeing thousands of candidates, she caught a glimpse of a camera-phone head shot sent in by a sixteen-year-old named Christopher Mintz-Plasse. She called the director, Greg Mottola, and excitedly said, “I think I found McLovin; he’s like Dill from ‘To Kill a Mockingbird.’ ” Jones told me, “You could tell he was a kid who probably had seen the inside of a locker.” Since then, Mintz-Plasse has starred in six movies.

“Allison doesn’t just find us actors; she finds us people we want to work with the rest of our lives,” Apatow said. “That’s good, because the older you get you don’t want to see tons of people. I know if Allison sends two they will both be great.” Feig said, “Years from now, she will be recognized as having changed the face of comedy as much as any comedy filmmaker. All the best comedy people have come through her or from her.” Jones did the casting for Apatow’s 2007 film, “Knocked Up,” and for Feig’s 2011 comedy, “Bridesmaids.” This summer, Feig will direct a remake of “Ghostbusters,” with all-female stars and a supporting cast assembled by Jones; already it’s the most highly anticipated comedy of 2016.

Jones is in her fifties, and nearly six feet tall, with unruly curly hair. In jeans and blouses from Liberty, she comes across as someone’s favorite aunt. She met Feig more than twenty-five years ago, when he was a struggling actor, and their professional relationship deepened through their collaboration on “Freaks and Geeks.” In 2013, Feig reacquired “Other Space” from Twentieth Century Fox Television, where it had been stuck for years. Feig once described the show in the Times as a sci-fi version of “The Office.” The lead character, Stewart Lipinski, is a dorky twentysomething space commander. He is assisted by Karen, his sister, and Michael, his best friend, both of whom are miffed at having been passed over for the position. The other crew members are Kent, a wealthy humanoid who has wakened from a chemical bath; Tina, Stewart’s ditzy love interest; and Natasha, a Spock-like virtual sexbot and the ship’s operating system, who appears on a computer screen.

By the time Jones finishes reading a script, she already has ideas about which actors might be right for the roles—and who can handle the pressure of constantly improvising during the eighty-hour workweek that shooting a television comedy often requires. But she also likes the surprise of the unknown, and on the first day of casting she was wading through fifty or so candidates chosen from some nine thousand who had appealed to her in online head shots. She was looking in particular for “Paul Feig types,” well-meaning nerds who are endearing in their benevolent oddness. “She finds people that your heart can break for,” the actor Paul Rudd told me. By lunchtime, however, Jones hadn’t seen anyone worth showing to Feig. “They’re forcing it,” she said. “It’s not real. You’re either a nerd or you’re not.”

Between auditions, to lift her spirits, Jones watched an old “Saturday Night Live” sketch of Will Ferrell spoofing James Lipton. At one point, she whispered, “I’m going to hit the ladies’ room and blow my brains out.” But she caught a glimpse of someone interesting in the waiting room, and when she came back her eyes were alight.

“Wait till you see the next guy! He’s a real goober. He’s the real thing. I just hope he can talk.”

Nick Azarian was a mountain of hair nesting on a tiny, teen-age face. He carried a binder and wore a turtleneck with a space-camp sticker. As he walked in, a wide smile broke across Jones’s face. According to his IMDb résumé, Azarian, who is from Charlotte, was a “full-out power geek.” He told Jones that he’d found the shirt at Goodwill and printed the sticker himself.