BoJack is a horse. His agent is a cat. His biographer is human. Illustration by Bendik Kaltenborn

When “BoJack Horseman” débuted, in 2014, it didn’t look particularly original. It was the hundredth series about a middle-aged man—well, a horse, but still—who did bad things. It was the latest scathing portrait of the downside of fame. It was the newest streaming dramedy: yet another adult animated alt-comedy meta-sitcom.

In an anti-antihero frame of mind, I took much too long to catch up on what turned out to be one of the wisest, most emotionally ambitious and—this is not a contradiction—spectacularly goofy series on television. Created by Raphael Bob-Waksberg, illustrated by the brilliant Lisa Hanawalt, and airing on Netflix, “BoJack Horseman” is a world-creation show, merging bleakness and joy. Like “The Simpsons” and its best descendants, “BoJack Horseman” uses animation to imagine a teeming, surreal alternative universe—in this case, a place called “Hollywoo,” in which animals and humans live side by side. BoJack, a former sitcom star, is a horse in a Cosby sweater; Diane, his sardonic biographer, is a human. Diane’s husband is a dog; BoJack’s agent is a cat; a bunch of whale strippers give lap dances in “the blowhole room.” Easily half the gags are silly animal puns, verbal or visual, like Broadway posters for “Fun Ham,” kangaroo bellhops, or a painting of Manet’s Olympia as a shark. The sheer density of these giggle-inducing, collect-them-all punch lines gooses the show’s more harrowing themes, as if Nathanael West had written “Miss Lonelyhearts” in puffy glitter ink.

The basic story is this: In the nineties, BoJack (voiced by Will Arnett) was the star of a network sitcom called “Horsin’ Around,” a hacky “Full House”-like series about a bachelor raising orphaned kids. Since then, he’s become a famous has-been, marinating in self-pity. This particular form of show-biz pathology has been explored a few times before; namely, in “The Larry Sanders Show.” In another familiar TV trope, in the first season BoJack fell into a love triangle, with Diane and her husband, Mr. Peanutbutter. The season took some gorgeous existential leaps, particularly in the second half, but had it stuck entirely to the P.O.V. of BoJack, a dyspeptic, near-suicidal know-it-all, it might have felt airless.

Instead, the show fanned open to multiple perspectives—among other things, during its brilliant second season it made the marriage of Diane and Mr. Peanutbutter feel as intimate as anything on “The Americans.” Meanwhile, BoJack fell in love with an owl his own age, a network executive who had just woken from a thirty-year coma. (When she met him, she said, “Who?”) He got cast in his dream project, a Secretariat bio-pic. Eventually, in one of the series’ most lacerating episodes, he landed in bed with his oldest friend’s teen-age daughter. Yet, magically, even as he trashed each opportunity, the series didn’t bog down in bleakness: it was sympathetic to BoJack’s depression and the sources of his pain, but it didn’t glamorize his solipsism as a special sensitivity.

Better yet, “BoJack Horseman” never stacks the deck by reducing more decent characters to dummies or dupes. Unlike lesser sad-guy shows, the series includes complex types like Princess Carolyn, BoJack’s agent and sometime girlfriend, a fortyish workaholic in a series of dead-end relationships (with BoJack, a cheating jackrabbit, and, most hilariously, Vincent Adultman, three little boys standing on one another’s shoulders under a trenchcoat). There’s also Todd, his sad-sack roommate; the indie-film director Kelsey; BoJack’s deer friend Charlotte, whose family he took refuge with when Los Angeles overwhelmed him; and many more—a true moral menagerie.

In certain ways, the show’s most original character may be not BoJack but his mirror image, Mr. Peanutbutter (voiced by Paul F. Tompkins), a yellow Labrador retriever* whose own awful nineties sitcom, “Mr. Peanutbutter’s House,” was a ripoff of “Horsin’ Around.” Unlike BoJack—but like many golden retrievers—he’s preternaturally enthusiastic, full of silly show-biz ideas but also happy just to sit at home watching “Bones,” his tongue lolling. Mr. Peanutbutter becomes the host of a game show called “J. D. Salinger Presents: Hollywoo Stars and Celebrities! What Do They Know? Do They Know Things? Let’s Find Out!” He’s been divorced twice, including from a horrible Jessica Biel, who bravely plays herself. Artistically, he has low standards. But he has a legitimate inner life. His openness to intimacy makes his wife, the unhappy Diane, itch. It also provides a goad to BoJack himself, suggesting that even for the rich and famous there are better ways to chase your tail.

The third season of the show, which recently appeared on Netflix, isn’t a masterpiece like the second: a few plot gears grind. But it lands powerfully, with an earned tragedy that’s as potent as anything on TV this year. Along the way, BoJack lobbies for an Oscar nomination at film festivals and at a bat mitzvah—for an actual bat. There are some classic installments, particularly an ingenious silent episode set at an underwater film festival, a riff on “Lost in Translation,” with sardines that cram into buses and a Chaplinesque subplot about BoJack acting as a midwife to a male seahorse. There’s a story in which Diane gets an abortion while the pop-star dolphin Sextina Aquafina, the “sexy fourteen-year-old dubstep wunderkind” for whom she’s been hired to write tweets, sings a hilariously rude pro-choice anthem. Again and again, the show takes sharp jabs at modern culture, including a delirious vision of a post-apocalyptic L.A. Times, with nothing left but customer service.

The show has always had a built-in risk: as effective as BoJack is as a character, he runs in circles. That’s what addiction is, after all. BoJack’s life is a formula, one that he feels desperate to correct: he’s ashamed of who he is, attempts to become creative or feel love—and then inevitably binges, betrays a loved one, and runs away, realizing that it’s impossible to truly repair the damage. Then back to shame. Repetition is the signature of sitcoms, too; it’s their curse and their power. On “BoJack Horseman,” again and again, someone’s life crashes, and he ends up on the living-room sofa, high, bingeing on reruns of “Horsin’ Around.” The cynical, knowing characters may mock that show’s cornball ways, but they’ve memorized every plot: it’s a shared set of memories much simpler and more comforting than the real ones.

On a junket, BoJack rages at journalists who call “Horsin’ Around” a bad show: “It lasted nine seasons! Its whole purpose was for people to watch it so the network could sell ad time so the show could make more money than it cost to produce. It did that well. It was a good show.” But BoJack knows that it has more meaning than that. It’s no coincidence that “BoJack Horseman” itself replicates the plots of sitcoms—Princess Carolyn goes on a series of bad dates, BoJack crashes a wedding—to inject them with something rawer and more unsettling. It does the same thing with jokes, messing with ancient comedy math so that the missing beat becomes the joke. “I’m the only albino-rhino gyno I know,” one of Princess Carolyn’s dates says, just before ordering a bottle of wine. “Oh, great, you’re also a wine addict,” she replies. It’s a clever joke for people who love dumb jokes.