But long before his images of street fashion became a regular newspaper feature, Cunningham spent eight years, from 1968 to 1976, working on a whimsical photo essay of models in period costumes posing against historic sites of the same vintage.
Astride his bike, he searched secondhand shops for antique clothing and looked for architectural sites across the city to create the perfect tableaux, many of which featured his muse and fellow photographer, Editta Sherman.
The result was "Facades," a book published in 1978.
Now, nearly all of the 88 gelatin silver prints from the series, which Cunningham donated to the New-York Historical Society, are featured in an exhibition there. "Bill Cunningham: Facades" runs through June 15.
A former hat maker, Cunningham's models are featured in fantastical headdress. In one composition, Sherman wears a fur pillbox that playfully mimics the spiral lines of Frank Lloyd Wright's Guggenheim Museum. In another, a large hat brimming with oversized feathers and flowers perched high on Sherman's head is used as a perfect counterpoint to the sculpture of Hercules, Minerva and Mercury on the clock atop Grand Central Terminal.
"I don't think he ever thought of it as a fashion project," said the show's curator, Valerie Paley. "It's more a social, architectural and fashion history of the city. ... He saw the grace of old architecture, the lines and the architectural integrity."
Architectural preservation in New York City was in its infancy when Cunningham began work on the photo series. Just a few years earlier, two of the city's masterpieces — the original Penn Station and the Hotel Astor (the Waldorf Astoria's predecessor) were demolished.
But while Cunningham may not have been making a statement about preservation, said Paley, "he certainly was seeing beauty where others weren't seeing it."
The exhibition also recounts some of the amusing stories of Cunningham's vintage clothing expeditions. One of his earliest finds was a 1770s mob-cap of white lace and taffeta that a thrift store had mistaken for a chair doily. He paid $2 for it.
A humble and private man, the 85-year-old photographer said at the exhibition opening that he rarely paid more than a few dollars for any of his finds.
"I'm crazy about fashion and I'm mad about architecture," he said. "It was all here in New York City."
Cunningham and Sherman, a celebrity photographer of famous artists and musicians who died at age 101 last year, were neighbours in the Carnegie Hall Studios, once live-work spaces for artists, musicians and actors above the famous music emporium. They often rode the subway to the various locations to avoid wrinkling the costumes. An amusing photo in the exhibition shows Sherman sitting in a graffiti-covered subway car resplendent in Victorian dress.
The "Facades" project demonstrates that Cunningham is "clearly somebody that knows the history of fashion thoroughly and is in love with all aspects of fashion, not just what's trendy this season but the esthetic value of fashion in any period," said Valerie Steele, director and chief curator of The Museum at Fashion Institute of Technology.
His interplay of fashion and architecture "just shows how much he knows," that fashion has to do with art, style and change over time, she added.
That knowledge is abundantly obvious from the pencil notations he jotted on the back of the prints.
In his evocation of the Civil War era, he wrote that the period's brightly colored fabrics were made possible by "the industrial revolution in textile dye from natural to chemical."
"Almost as an anthropologist," Paley said, Cunningham recorded his field notes about the history of the buildings and the costumes.