There is a scene in the new documentary “I Am: Celine Dion” in which Ms. Dion describes her dedication to designer heels.

“When a girl loves her shoes, she always makes them fit,” the singer said, spreading her fingers to demonstrate how she has contorted her toes to accommodate shoes ranging from size 6 to 10. Asked for her size while shopping, she said, she would respond to sales associates: “What size do you have? I’ll make them work. I’ll make them fit.”

It is a feeling well-known to women who relish playing dress-up: determination so great it pushes up against delusion.

That was certainly the feeling at Marc Jacobs’s runway show Monday night, held at the New York Public Library. Fashion is determined to be a joyful medium, even or especially when the world seems joyless. And Mr. Jacobs was determined to dress his models like surreal dolls of 20th-century American iconography.

A heavy white Marilyn Monroe dress opened the show. Its bodice was oversize, with pointy bra cups and a skirt sculpted in permanent half flight. Marilyn walked in white sandals made to appear about an inch too large in every direction, like a girl insistent on wearing heels from her mother’s closet. (“I walk the shoe, the shoe don’t walk me,” as Ms. Dion would say.)

The proportions were a continuation of Mr. Jacobs’s February runway show: big and cartoonish, like a joke we’re all supposed to be in on. Models seemed to be tensing to keep their thick clothes in place, though of course they fit just as Mr. Jacobs intended. Necklines were lifted by invisible fingers off the shoulders of Peter Pan-collar jackets, preppy V-neck sweaters, voluminous floral cocktail dresses. Saccharine bikinis — one in white pointelle, pinned with a photorealistic daisy brooch, and the other in yellow polka dots — swung and jutted off the body.

Occasionally these proportions seemed devilish. Some shoes had horned toes. The models could not fully open their eyes, which were covered with thickly lashed pastel-painted pads, like a commentary on women blinded to the world by their obsession with beauty. (Or maybe, as the stylist Gabriella Karefa-Johnson suggested on Instagram, it was just a homage to Miss Piggy.)

Though sometimes subversive — Mr. Jacobs can make a pretty eyelet dress look deranged — the collection was fundamentally optimistic. The designer opened his show notes with a single sentence: “Joy, period.” He wrote about seeing fashion as a path to a “deeper pursuit of joy, beauty and personal transformation.” He covered Cardi B, a guest, in a cloud of purple and yellow flowers.

Mr. Jacobs’s personal transformation lately includes wearing long nails that can be seen and heard (the rhythmic clacking!) from yards away. On Monday, his nails were French-manicured, their tips covered in gems resembling a few embellished pieces in the collection, including a miniskirt suit.

On the miniskirt suits: The most gossiped-about subject in fashion is still who will take over Chanel following the departure of the artistic director Virginie Viard. Mr. Jacobs, who incorporated quilted handbags into the show Monday night, is one of many names that come up in conversation — perhaps not among the top three suspects, but somewhere in the top 10.

While none of the contenders have publicly commented on the speculation, some eyebrows were raised by these words in Mr. Jacobs’s show notes: “The future remains unwritten.”