Ilona Royce Smithkin, who as an orange-haired nonagenarian with matching two-inch eyelashes caught fire in the world of fashion, starring in a documentary film and joining fashion campaigns for brands like Coach, while flinging embers into many other fields as a muse for photographers, filmmakers and entertainers, died on Aug. 1 at her home in Provincetown, Mass. She was 101.

The death was confirmed by Melinda Levy, a longtime friend and a trustee of her estate.

Ms. Smithkin’s rise to fame began with a rumor.

In 2010, the photographer Ari Seth Cohen, who created Advanced Style — a blog devoted to the style of women over 60 that later became a book series and a movie on the same topic — heard from a friend about a “magical woman with fiery red hair and the longest eyelashes anyone had ever seen.” He staked out a store she was said to visit.

Not long after, he spotted a woman on the street in the West Village of Manhattan who was about 4 feet 9 inches tall and wore hand-painted sneakers, matching baby blue clothes and diamond-studded sunglasses, with eyelashes poking out. It was her.

Mr. Cohen asked to take Ms. Smithkin’s photograph. She exclaimed, “Of course,” and kicked a leg in the air.

“I instantly fell in love,” Mr. Cohen said in a phone interview.

He began visiting Ms. Smithkin’s fourth-floor West Village walk-up, a tiny studio so crammed with fabrics, handbags, paintings, magazines and hats that the door could not fully open. Ms. Smithkin served coffee or vodka — “the only two things I know how to make,” she explained — and described how she fabricated her own caftans and turned objects like letter organizers and typewriter springs into jewelry.

Without any intent to make a movie, Mr. Cohen and a friend, Lina Plioplyte, began filming their conversations with Ms. Smithkin. That became, in 2014, a documentary, “Advanced Style,” focused on some of the blog’s principal recurring characters.

In the movie, Ms. Smithkin, a painter by profession, combined arresting personal disclosures with slapstick comedy. “I came into my own about maybe 10, 12, 13 years ago,” she said, although she was 94 when it was released. She joined a nonagenarian friend, whom she said suffered from memory loss, to sing as a duet “You Make Me Feel So Young.”

“I don’t think ‘Advanced Style’ would have been a fraction of what it is without Ilona,” Mr. Cohen said. “She brought it a depth. She was the star.”

Ms. Smithkin started modeling, appearing in campaigns for eyewear by Karen Walker and clothes by Mara Hoffman She was labeled a “92-year-old style legend” by The New York Post’s Page Six.

To those boogieing at the Jane Hotel in the West Village, Ms. Smithkin might have seemed a figure from vaudeville, her flamboyant get-up amusing enough for a turn in the spotlight. But she had a “stable of mentees,” consisting largely of artists, who knew better, said one of them, the actor Erik Liberman.

“She noticed who was pulled in by the color and light, and who wanted to understand the source of the color and light,” Mr. Liberman said. “For those who sought deeper conversation, off came the hats, the fabulous scarves and eventually even the eyelashes.”

Mr. Liberman often showed up at Ms. Smithkin’s studio at a moment’s notice to take naps between Broadway performances. When, as an aspiring actor in his late 20s, he began spending time with Ms. Smithkin, he brought along notebooks to record what she said. She instructed him to take his own creative powers seriously, rather than view acting as a form of subservience to someone else’s vision.

“That altered the entire course particularly of my young career,” Mr. Liberman said.

Ms. Smithkin was born Ilona Rosenkranz on March 27, 1920. Her father, Mordko, was an engineer; her mother, Frida (Lubinski) Rosenkranz, was a homemaker.

That information comes from immigration documents. In April 1938, the family moved from Berlin, where Ilona had grown up, to New York. They listed their race as “Hebrew.”

As an adult, Ms. Smithkin avoided discussing her background, saying when prompted that she had few recollections. But in a 2004 documentary about her, “Ilona, Upstairs,” she attributed the way her head shook sometimes involuntarily to experiences she had as an 11-year-old when the Nazis began their rise to power.

“It’s not Alzheimer’s, it’s not Parkinson’s,” she said of her shaking. “That is that terrible, repressed fear.”

In the United States, her parents Anglicized their names to Max and Frieda, and the family surname became Royce.

According to Ilona’s early-1940s petition for naturalization as a citizen, she was born in Berlin, but she later said that she had been born in Poland. She began making art when she was about 5, and she studied at the Reimann School of Art and Design in Berlin, the Royal Academy of Fine Arts in Antwerp, Belgium, and the Art Students League in New York.

A year after immigrating, when she was 19, Ilona married Irving Smithkin, a linotype operator. He died fighting in World War II and was buried in Italy.

Ms. Smithkin painted and made a living as a milliner, a factory worker, a painter of glass lantern shades and a movie theater usher. She moved into her West Village studio in 1947.

In the 1960s and ’70s, she began teaching art classes in Kentucky and South Carolina, traveling to small towns and using church basements and funeral parlors as classrooms. In 1975, she began holding painting classes on the South Carolina Educational Television Network.

When she was not on the road, Ms. Smithkin split her time between the West Village and Provincetown. She met and made portraits of writers like Tennessee Williams, Eugene O’Neill and Ayn Rand.

In interviews, Ms. Smithkin referred to having a revelation and finally becoming her authentic self around the age of 80, roughly the same time she started performing songs by Marlene Dietrich and Édith Piaf in Provincetown and at New York venues like Joe’s Pub. She would wear stilettos, stockings and a revealing dress, and until she had hip surgery in her mid-80s, she finished every show by doing a split.

By her own admission, she did not have much of a voice — but neither, she said, did Dietrich.

Ms. Smithkin leaves no immediate survivors, but she did develop a ritual for marking someone as part of her inner circle.

You entered her studio and sat on a chair next to her bed. She studied your face. She selected a pencil. Then, for about 20 minutes, you held still while she drew a portrait of one of your eyes.

“You talk; I want to hear about you,” she would say while drawing, according to “Insomniac City,” a memoir by the photographer Bill Hayes in which he describes sitting for an eye portrait. “At this moment, you are the most important person in the world.”

It was, he said, a “spiritual experience.”

Alain Delaquérière contributed research.