Betty Gilpin is perched elegantly on a stool, lips pursed and eyes narrowed to camera, when an idea strikes and she clambers to the floor. Down on all fours, she slings a tablecloth over her head like a child inside a blanket fort. Regulars at Sardi’s, a Midtown haunt plastered with caricatures of the theater-famous, hardly blinked.

Gilpin knows how to work a photo shoot — and, more important, for her recent Broadway debut — she’s not afraid to look stupid.

“Gina Gershon and a flower that squirts water in your eye, those are my two modes,” she says.

That’s self-deprecation talking. Glipin’s breakout role, as a soap star turned body-slammer on the bubbly and arch series “GLOW,” demonstrated jaw-dropping strength and protean emotional range. She landed three consecutive Emmy nominations (Netflix scrapped the fourth season due to the pandemic) and caught Hollywood’s attention.

Gilpin, 38, has since become an indispensable fixture of out-there hidden gems on second-tier streamers. On Peacock’s “Mrs. Davis,” she’s a wry nun determined to destroy an omniscient bot. Over on Starz, she’s a coiffed and frank Mo Dean in the Watergate thriller “Gaslit,” starring Julia Roberts, and a housewife whose repressed desires explode like a firework in the adaptation of Lisa Taddeo’s book “Three Women.”

Through all of Gilpin’s work, torrents of feeling course thrillingly close to the surface. Tears are often flicked away like an afterthought. She can do deadly serious and be an outrageous goofball, and doing both at once is something of a specialty.

Last month, Gilpin began an eight-week run in the hit Broadway comedy “Oh, Mary!” giving what the show’s director Sam Pinkleton calls “a chaotic, genius performance” as the alcoholic and fame-hungry Mary Todd Lincoln. She is the first actor to replace the show’s writer Cole Escola, a daunting feat given the singularity of Escola’s celebrated turn in a role they created for themselves to play.

Gilpin also returned to Netflix in “American Primeval,” a brutal western from “The Revenant” writer Mark L. Smith, as a fiercely protective mother crossing battle lines between Mormons, pioneers and Indigenous peoples. The series has drawn critical acclaim and hovered among the platform’s most-watched since its January premiere. “It’s been almost two years of me screaming in a corset and skirt the size of a kitchen island,” she says.

In person, Gilpin is present and relaxed but considers her words carefully. She is acutely self-aware and hyperarticulate. Speaking between spoonfuls of matzoh ball soup, she distills the complexity of her experience into imaginative metaphors that reflect a spiky and penetrating sense of humor. In her 2022 book of essays, “All the Women in My Brain: And Other Concerns,” Gilpin likens her early career experience to “walking through the world as an apologizing Barbie” trying “to give whoever is in front of you the girl they want.”

Grueling in their own ways, her new projects mark another breakout of sorts — further beyond the limitations Gilpin has bristled against her whole career. Free from the pressures of having to be “the horniest poodle in the room,” she’s content to be entering her “playing mom with arms crossed” era. Becoming a mother reordered her sense of identity and made reaching into her imagination feel more immediate. (The elder of her two daughters is 4.) “Having kids, that door to your psyche is sealed open and all your demons and hopes are floating in and out, even when you’re in line at CVS,” she says.

More than death, what scares Gilpin most is not doing the scariest thing she can think of. Right now, that’s barreling onstage in an idiotic beast of a role that’s the toast of the Broadway season. “There’s no choice but to take an instinct by the throat and hurl it at the second mezzanine. It’s so intoxicatingly freeing,” she says. “I’m being handed the opportunity I’ve been shaking my fist at the sky that I never got. I feel simultaneously petrified and more ready than I’ve ever been in my life.”

On its face, Mary Todd is a deeply silly part in a supremely ridiculous show. She’s petulant and self-absorbed. She drinks a bucket of paint thinner, throws it up and then drinks it again. Never mind that there’s a Civil War on, she wants to do cabaret, insisting with obvious delusion that she used to be a “niche legend.” She’s also completely relatable.

“Mary is desperate for her chance to phoenix into her most on-fire self and terrified of what she’ll find out about her own mediocrity,” Gilpin says, comparing Mary’s experience to her own journey taking over the part. “Even though it’s the stupidest play ever to exist, it’s also so flawlessly true: We all are terrified of asking the question, ‘Am I magnificent or not?’”

When Gilpin first saw the show downtown ahead of its record-breaking transfer to the Lyceum Theatre, Escola’s daring and originality moved her to tears. “I’m watching someone do the impossible, which is knowing themselves enough to reach into their soul and say, ‘It doesn’t look like anyone’s you’ve ever seen and it also looks exactly like yours,’” Gilpin recalls. “It just made me cry and think: All I can hope for for my kids is that they know and like themselves enough to do that.”

Escola, who drew raves in the part, said over email that casting Gilpin was “a dream come true. … Imagine you’re playing alone in your room with a Vivien Leigh Barbie and then Vivien Leigh taps you on the shoulder and says, ‘Hey can I play?’”

“She’s an actor of tremendous gravity,” says Pinkleton, the director. “She’s like an old-school clown — she can’t tell a lie.” Onstage, Gilpin’s Mary is like a ferocious and frightened caged animal whose cruelty to everyone around her feels rooted in pain. Raw, trembling and pulsing with desperation, it’s a very different performance from Escola’s Mary, who seemed to exist on a twisted planet of her own making.

“It felt INSANE,” Gilpin writes in an email the morning after her first performance. “I was on two parallel tracks of ‘frothing hamster’s rabid dream coming true’ and ‘terrified actress panicking about forgetting x prop,’ and really should have peed one more time.” Afterward, she sobbed.

Gilpin’s return to theater, where in the 2010s she appeared off-Broadway in plays by Sam Shepard and her friend Zoe Kazan, also marks a return to the family trade. The eldest of three siblings born to New York actors, Gilpin recalls shouting “Thank you, five!” while getting ready for school as though responding to a five-minute alert backstage, where she spent childhood evenings enthralled by dressing room gossip. Gilpin’s mother, Ann McDonough, was last on Broadway in “The Ferryman”; her father, Jack Gilpin, who currently plays a butler on “The Gilded Age,” also made his Broadway debut at the Lyceum.

They insisted she try different things as a kid — “my parents would not allow me to be the Shirley Temple with the eyes of Joan Crawford that I wanted to be” — but she got her first movie part by tagging along with them to an audition while studying theater at Fordham University in Manhattan. (The actor who played her brother, Cosmo Pfeil, would later become her husband.)

The small roles she landed while finishing her credits — including a dead body and a teacher who sleeps with her student on different versions of “Law & Order” — were a lesson in narrow opportunities for women on-screen. Faced with the paradox of resenting the industry’s demands while knowing they were her way through the door, she dyed her hair blond and started wearing tight clothes to auditions.

Gilpin landed her first major TV gig as a promiscuous doctor on three seasons of Showtime’s “Nurse Jackie,” serving as a young foil to the prickly antihero played by Edie Falco. But in the decade since, Gilpin has become known for taking on roles that defy stereotypes and delve beneath the surface of female desire. (On the Apple TV Plus series “Roar,” she plays a woman placed on a mantel by her husband — a literal trophy wife — who climbs down and smashes the shelf to pieces.)

“GLOW” co-star Alison Brie recalls watching Gilpin — now one of her “closest friends and soulmates” — grow more confident over the course of filming, which pushed them to physical extremes while giving their characters meaty arcs. “She taps into such power when she’s working, and I watched her become aware of it and allow herself to take up more space when the camera wasn’t rolling,” Brie says. “It was a big change to see her feel deserving of the spotlight.”

With that attention came the absurd controversy surrounding “The Hunt,” a bloody 2020 satire from Blumhouse that imagines liberals killing “deplorable” conservatives for sport. Gilpin’s lead role as a renegade survivor cemented her bona fides as a gonzo action hero. But promotion for the film drew backlash from President Donald Trump and its release was another casualty of the pandemic. The film’s director Craig Zobel describes Gilpin’s performance as part Linda Hamilton and part baby dinosaur.

In “American Primeval,” Gilpin plays a more conventional role — a mother charging through the frontier in search of her husband — but with the grit and emotional urgency she brings to each one. Series director Peter Berg praised her “boundless energy” and professional commitment, particularly after production shut down due to the Hollywood strikes and resumed when she was six months pregnant. “She always brings a tremendous level of creative enthusiasm,” Berg says. “She’s there for the work and she’s up for anything.”

“She throws caution to the wind. She’s very raw and every take is different,” says Taylor Kitsch, who plays her character’s hired horseman. “With the amount of pressure she puts on herself, she’s going to be overprepared and take a f—ing swing.” The two are eager to team up again and have been throwing around ideas, including Broadway. “Knowing us, we probably want to scream and f—ing cry and go through a divorce like no one’s seen before,” Kitsch says. (Albee, anyone?)

Back at Sardi’s, Gilpin reflects on a day of self-promotion (next stop, “The Late Show With Stephen Colbert”). It’s clear that she is continuing to evolve — away from presenting the version of herself that she thinks people want to see and into someone who doesn’t care whether her multitudes are showing. “An interesting part of whatever B-level success I’ve had is suddenly a lot of it becomes about performing your identity. But thinking about how you’re perceived is the antithesis of what makes a thing good,” Gilpin says. “I want to keep trying not to check the mirror to see if my authenticity is selling.”