I kept looking over Meryl Streep’s shoulder. She is by common reckoning the greatest actress alive, and her character in the movie version of August: Osage County—a snarling, spitting, dying, pill-popping matriarch from hell—was the laboratory specimen of an Oscar role. But it was the rivetingly frumpy woman in a shapeless print blouse and oversized sunglasses who really held my attention, starting from the moment she swept into the Oklahoma house where the movie is set bearing a store-bought angel food cake and commanding her meek husband to “feel my back. Sweat’s just drippin’ down my back. Feel it!”

August: Osage County was released in 2013, and I suppose I can be faulted for experiencing my Margo Martindale epiphany so late in her long career. This was two years after she had already won her first Emmy for her role in the FX drama Justified as Mags Bennett, the deeply empathetic if coldly murderous head of a criminal clan in the hills of Kentucky. Martindale is from Jacksonville, a town situated far enough into East Texas to give her a crucial credibility boost when it comes to playing Mags or any of the other Southernish characters that make up her specialty zone.

Her appearance helps too. We live in a time when it is more possible than ever, as Leonard Cohen sang, to be “oppressed by the figures of beauty.” During the course of an average day, via television, movies, magazines, and Internet pop-up ads, we are besieged, engulfed, taunted by pulchritude. The sort of luminous beings that we might encounter in real life only once every year or so come rushing at our eyeballs by the thousands. It’s no accident, of course—human perfection is naturally commanding. But in a culture in which beauty is also wallpaper, a normal-looking person like Margo Martindale holds the advantage of surprise. The fact that she is 64 with a forthright BMI and an intriguing though not arresting face means that when you finally notice her you really notice her. She belongs to our tribe. She’s one of those rare screen presences that end up being everybody’s secret discovery.

After taking a look at the list of her acting credits over the decades and realizing how often I must have seen her onscreen without that crucial discovery taking place, I recently sentenced myself to Margo Martindale re-education camp. This was far from an ordeal, though I did have to watch Hannah Montana: The Movie, in which Martindale provides grandmotherly counsel to a young Miley Cyrus as she sets out on the long (and, as of this writing, still unconcluded) journey in search of her authentic self. Elsewhere she was hiding from me in plain sight, as a waitress in The Rocketeer, a psychologist in The Human Stain, a bitter, tyrannical mother to Hilary Swank in Million Dollar Baby. In Lonesome Dove she made a brief appearance (not nearly as brief as mine, but that’s a footnote for another day) as a prostitute in Ogallala, Nebraska, named Buffalo Heifer. Sporting wildflowers in her hair and a cowbell around her neck, she teasingly asked a group of bashful young trail drivers if they wanted to “ride the buckin’ pony.”

Waitress, mother, grandmother, whore, nurse, therapist, farmwife, best friend, housekeeper: these are the plain people that actors like Margo Martindale are inevitably slotted to play. But all you have to do is watch the second season of Justified to witness how, when it’s entrusted to the right actor, a character role can take on enough steam to render irrelevant the boring above-the-title hierarchy of leading men and leading women. Martindale’s Mags Bennett doesn’t dominate the story—the show’s got a strong ensemble cast and good writing—but this sorrowful mother of three mostly useless sons, with a marijuana empire to protect and ancient grudges to monitor, has an anchoring complexity. Her eyes are pleading, her hair is done up in a lusterless pile, her wardrobe is a succession of faded dresses and clog-like shoes and untucked shirts cinched around the waist with a man’s belt. She’s greedy and double-crossing but also weighted down with what you can’t stop yourself from thinking might be genuine human warmth. If you don’t have time for a complete binge-watch, just check out the end of the first episode of season two. There you’ll find Martindale in peak Mags Bennett form, as she dispatches a weed-growing rival with poisoned moonshine and sits there holding the startled man’s hand, soothing him as he dies and even promising to raise his teenage daughter. “All the troubles of your hard life,” she promises with angelic softness, “it’s all gone now. You get to know the mystery, Walt.”

A purring, placating surface that masks a dangerous underside is something that Mags Bennett has in common with several other recent Martindale roles. On The Americans, another critically lauded FX series, for which she won her second Emmy in 2015, she plays the enigmatic handler for a nervous young Soviet spy couple living in suburban Washington, D.C. As the series begins, she is all bland reassurance, but episode by episode her character grows darker and wearier and more direct. “I know you better than you know yourself,” she finally levels with the agent played by Keri Russell, “and you don’t know me at all.” The moment she speaks those words, you feel them confirmed. It’s her pleasant, nothing-special face that makes this declaration vibrate with such mysterious authority.

Ruth Eastman, Martindale’s recently introduced character on the current season of CBS’s The Good Wife, is fathomless in her own busy-busy, lighthearted way. She’s a political operative—“the miracle worker of Iowa”—who has been brought in to manage the presidential campaign of the can’t-keep-it-zipped governor (Chris Noth) who is the estranged husband of the title character, played by Julianna Margulies. The story line intrudes upon today’s real-life primary season with daring specificity. “We could win!” Ruth tells a rival operative over Alabama slammers. “Things turn sour for Hillary—the emails—and the next thing they throw at her, we win!”

Ruth Eastman is certainly more presentable than Mags Bennett (if I were to go out on a mansplaining limb, I’d say she shops at Chico’s), but when it comes to playing the sinister long game, they’re sisters in strategy. Although Ruth, unlike Mags, is a celebrated power player, she seems to revel in the value of low-glamour expectations. In the chilly law offices where much of The Good Wife takes place, where all the women are toned of form and taut of face, Martindale’s denser center of gravity can have a distorting effect, throwing all those sleek heavenly bodies into orbital wobbles of uncertainty.

Not every show benefits equally from the Martindale effect. She had a leading role in a comedy series called The Millers that aired for two seasons on CBS before being canceled in 2014, but you never had the feeling she was indispensable. Mostly this was because the show itself was so dispensable. Martindale played a newly separated woman with boundary issues who moves in with her son, goading him into dancing with her to the sound track of Dirty Dancing and saying things like “Apparently I passed gas recently.” That’s all in the pilot, which is as far as I got. Pardon me for not making an effort to become a Millers completist, but I needed to move on to BoJack Horseman, an animated series of deadpan surrealism soon to begin its third season on Netflix. BoJack is sort of impossible to explain, as you can see from the following explanation: it’s about the adventures of a humanoid horse in an alternate mixed-species universe who happens to be the washed-up star of a nineties sitcom called Horsin’ Around. Martindale is sporadically inserted into this equine version of Curb Your Enthusiasm as an animated character who goes by the archly knowing name of Character Actress Margo Martindale.

It’s a measure of the real Margo Martindale’s increased visibility that she can now be presumed to be so well known that her continued anonymity is an insider joke. “Sure, of course, everyone loves my work,” she sneers in her cartoon form, just before opening fire during a robbery at the cops who, it turns out, are big fans but can’t quite place her. “But apparently not enough to watch the credits and find out what my name is.”

Real or animated, Margo Martindale shouldn’t sweat it. Maybe not everybody has yet caught on to who she is, but that only means they still have the opportunity to experience what I did when I first caught sight of her in those opening scenes of August: Osage County. She possesses the power to deliver what few other performers can: the shock of the normal.