When I set out to write about the making of Midnight Cowboy, the gritty, groundbreaking X-rated drama that won the best-picture Oscar in 1970, I expected to focus on director John Schlesinger and on Dustin Hoffman and Jon Voight, whose powerful performances are among the finest in film history. But I soon discovered a parade of talented men and women who played pivotal roles in making the movie great.

None more so than Ann Roth. The wildly inventive costume designer created memorable outfits for Ratso Rizzo, a tubercular petty thief from the Bronx played by Hoffman, and Joe Buck, a hopelessly naïve male hustler from Texas played by Voight. Roth has been one of the premier designers for movies and theater for more than a half-century and is still going strong—when I met her at her eastern-Pennsylvania farmhouse, she had three shows opening on Broadway at the same time. While making me a perfect omelet, she talked about dressing Hoffman with undisguised pride, as if it were yesterday.

Roth told me she starts from a simple premise: she doesn’t just make costumes; she makes characters. The idea was to find the clothes Ratso would have bought from the places he would have bought them—or, in his case, the places he might have stolen them from.

Hustlers with style.

Roth figured that if you were a roustabout Italian kid from the Bronx, you wanted to look like Marcello Mastroianni, the beautifully dressed star of Federico Fellini’s La Dolce Vita and 8 ½. Which meant you likely wore a white suit.

Next door to the Port Authority Bus Terminal, she bought a pair of folded white pants with a line of gray dirt along the crease of each leg from a sidewalk table for $12. Further up 42nd Street she found a pair of shiny, high-top black shoes with pointed toes. “They were cockroach-in-the-corner shoes,” she said. “I had to have those.” Then she bought a Continental-cut sport coat that looked to her like some high-school kid had rented for his prom and then chucked into a trash can after he threw up on it. “It was mambo and the cha-cha-cha and all that, a short jacket and a very skinny little behind.”

When Hoffman, fresh off the premiere of The Graduate, walked into a fitting room at Eaves Costume Company on West 46th Street, one of Roth’s favorite haunts, she said to him, “You and I are gonna find this character together.”

“The truth is, you as a designer know what you want them to look like, but you also know that if they don’t go along with it, it’s not going to look good,” Roth said. “And so what happens is I say, ‘Listen, close your eyes, close your mind, and be a dummy, let me just play.’ And it ends up there are, like, five different pairs of shoes on the floor, here is some crappy jewelry in a dirty box, here is a box of shirts, and the pants, and you say, ‘Put that on now.’”

Costume designer Ann Roth made Voight’s suede jacket herself.

The result: “You’re looking in the mirror and you don’t see Dustin Hoffman anymore, there is someone else. I remember doing dirty fingernails on him. I didn’t ask him. The pompadour was a little bit up. And I said, ‘Put this shirt on, don’t tuck it in all the way, just make it messy.’ You look into the mirror and here’s this guy who could easily sleep on a pool table. And that’s what you’re after.”

Roth used the same process with Jon Voight. “Joe Buck lives with his grandmother. His pants come from Montgomery Ward. That’s his best shirt; she gave it to him for Christmas,” she said. “Joe’s clothes were cheap, and I wanted them to look cheap.” She made Joe’s iconic suede jacket herself as well as his cherished cowhide suitcase.

“Neither one of these guys was difficult,” she recalled. “There are actors and there are movie stars, and I don’t work with movie stars. These guys were really good actors.”

Costume designer Isis Mussenden, a member of the board of governors of the Motion Picture Academy, says Roth “helped create a new template for costume design…. Once you bring in Ann Roth, who is brazen, incredibly brilliant, and a little bit mad, it’s a whole different beast.”

Glenn Frankel is the author of numerous books. His latest, Shooting Midnight Cowboy: Art, Sex, Loneliness, Liberation, and the Making of a Dark Classic, will be published on March 16 by Farrar, Straus and Giroux