The influence of Louis C.K.’s sitcom has upended notions of what the form can be. Illustration by Dan Adel

To his fans, Louis C.K. is more than just an artist. He is Lenny Bruce, he is Bob Dylan—the performer who serves the truth raw, not cooked. It’s a reputation that could rankle, if the man didn’t pretty much deserve it. If you’re not familiar with him, Louis C.K. (short for Szekely) is the country’s best standup. With a radical level of productivity (he generates an hour of new material per year, then discards it), Louis has built a confessional act that covers the birth of his kids, his divorce, and his rancorous arrival into middle age—with the odd political leap, like the time he peppered Donald Rumsfeld with questions about whether he and Dick Cheney are “lizards from outer space who eat human flesh.”

In 2010, Louis C.K. created the sitcom “Louie” for FX, the show that transformed him—at least for those of us in the church of the sitcom—into a modern saint. It wasn’t his first time on television, but over the years he’d become fed up with the sour collaboration of sitcom and late-night-show writers’ rooms. In 2006, he created and starred in HBO’s “Lucky Louie,” a bleak deconstruction of “The Honeymooners,” which won praise from critics but was cancelled after one season.

That show led to “Louie,” the stripped-down half hour he occupies on FX. The channel gave him an unheard-of deal: a tiny budget in exchange for total control, to the point that Louis doesn’t even get notes from network executives. For the first two seasons, Louis wrote, directed, edited, and starred in every episode, and was also the music director. The result was a series that, despite its small audience, has had a broad influence, upending notions of what a sitcom can be. (Among other things, it helped inspire Lena Dunham’s “Girls.”) Like his standup act, Louis’s sitcom is melancholic, profane, and hilarious, shifting in tone from week to week. Scored to jazz, the show can be lushly cinematic (Louis’s roots are in independent film), then loose and skitlike. There are slow passages, and sequences that lean too hard on self-pity, but there are many more moments of crazy transcendence, plus a fart joke or two. “Louie” takes risks rare for television, including the risk of not being perfect.

Season 1 was good; Season 2 was better. Louis plays a lo-fi version of himself, spending his days drifting through New York, brooding, bingeing on ice cream, slumping in wintry playgrounds, like Charlie Brown with a buried temper. As Season 3 begins, he has begun dating, his daughters are older, and he has some money (enough to buy a motorcycle). But the biggest change has taken place offscreen: Louis hired as editor Susan E. Morse, who has worked for Woody Allen. As impressive as the solo-built TV model is, it’s exhausting to maintain—and, perhaps for this reason, the third season of “Louie” is a revelation. It’s so good I’m afraid to praise it too highly, for fear you’ll be let down.

The new episodes start well, then keep improving, with narrative clarity and a fresh visual beauty. The first one, which aired last Thursday, opened, as the episodes often do, with his standup act. It’s a shaggy-dog routine that begins with Louie miming masturbation, then looking down to see that his penis is blurry: he needs reading glasses. Somehow this builds up to a riff about rich men buying new penises. “I don’t mean like a synthetic, kind of transvestite, kind of pink peapod, Frankenstein, grafted-off-your-leg dick,” Louie says, laughing, controlling the audience like an orchestra. “I mean: some dead kid’s dick. On your body. Like a happy ending to a sad story, on your body.”

One scene later, we’re in a Manhattan diner, where Louie has none of his onstage swagger: he’s silent, repressed, and twitchy. (In the past, the show has sometimes been sentimental about Louie as sad sack, but the new episodes feel smarter and tougher about his state of mind.) Louie’s dating April, a girlfriend we haven’t met before, and in minutes their relationship dissolves, as she interprets his grimaces like a soothsayer. “What is this, a game of relationship charades?” she kvetches. I’ve seen sitcom breakups before, but the rhythms here are very different, helped by a great performance by Gaby Hoffman. There’s a brief shot from outside the window, with a rush of traffic that lets you into Louie’s head. The dialogue is alienating, to the point of discomfort, but funny. Then suddenly, as April actually starts to do this thing—to break up with herself—a guitar swells. Rhythms slow; she looks shocked. There’s a closeup of Louie’s thumb, pressed against an ice-cream spoon. When April leaves, Louie walks outside to find his car getting crushed by a city vehicle, the hood crumpling under a metal arm—a stunt so obviously expensive for this low-budget series that I gasped. It also felt like a callback to a solid bit from Season 1, in which a water bottle tumbling from a high window crushed a different car.

Later, we get a glimpse of Louie’s ex-wife, Janet, something he had said might never happen. Last season, Louie’s sister described her as “that pasty, big-titted, black-eyed Guinea bitch,” but when she shows up she’s played by a black actress. The show has made playful gambits like this before, casting two actresses as Louie’s mother, adding a niece who was later deleted. The second episode burns into your brain, fuelled by a truly wild guest performance by Melissa Leo. The third episode, which is set in Miami, features a gorgeous, wordless sequence at dusk, as fat bald men like Louie gather to swim once the hard bodies have packed up for the night. That story edges toward sentimentality, then veers into something stranger: an affecting meditation on human intimacy.

The fourth episode is also terrific. And then comes the fifth, which is so good that I don’t even want to talk about it, which puts me in an odd position as a critic. (On Twitter, I said the episode was so good “it beat the previous episodes to death.”) So, you know, go watch it. Maybe you won’t like it as much as I did: it happens. I just want you to find it for yourself. We can come back and talk about it later.

For a different take on sitcoms, try “Episodes,” now entering its second season, on Showtime. Unlike “Louie,” “Episodes” uses sleek, standard joke structures: it resembles shows like “Friends” and “Mad About You,” which the creators, David Crane and Jeffrey Klarik, helped run. But “Episodes” has a sly subversiveness that deepens over time, like mercury poisoning: it’s an adult farce that is at once frothy and acerbic. It’s a bit like what HBO’s “Veep” seems intended to be, but with greater affection for its characters.

In the first season, a British screenwriting couple, Sean and Beverly Lincoln (Stephen Mangan and Tamsin Greig), arrive in Hollywood to remake their sophisticated hit sitcom for Americans—an easy payday, they imagine. Instead, they find themselves destabilized by smiling liars, deluged by network notes, and overseeing the development of “Pucks!,” a terrible sitcom that stars Matt LeBlanc (who plays a version of himself) as a hockey coach. Worse, their marriage topples, upended by a Los Angeles culture they’d imagined themselves entirely superior to.