Cunningham dropped out of Harvard University in 1948 and moved to New York, where he initially worked in advertising. Not long after, he quit his job and struck out on his own, making hats under the name "William J." After being drafted and serving a tour in the U.S. Army, he returned to New York and got a job writing for the Chicago Tribune. During his years as a writer, he contributed significantly to fashion journalism, introducing American audiences toAzzedine Alaia and Jean-Paul Gaultier. While working at the Tribune and at Women's Wear Daily, he began taking photographs of fashion on the streets of New York. As the result of a chance photograph of Greta Garbo, he published a group of his impromptu pictures in theTimes in December 1978, which soon became a regular series. His editor, Arthur Gelb, has called these photographs "a turning point for the Times, because it was the first time the paper had run pictures of well-known people without getting their permission."
Cunningham photographs people and the passing scene in the streets of Manhattan every day. Most of his pictures, he has said, are never published. Designer Oscar de la Renta has said, "More than anyone else in the city, he has the whole visual history of the last 40 or 50 years of New York. It's the total scope of fashion in the life of New York."[3] Though he has made a career out of unexpected photographs of celebrities, socialites, and fashion personalities, many in those categories value his company. According to David Rockefeller, Brooke Astor asked he be invited to her 100th birthday party, the only member of the media so honored.
In 2008 he was awarded the title Officier de l'ordre des Arts et des Lettres by the French Ministry of Culture.
In 2010, filmmaker Richard Press and Philip Gefter of The Times produced a documentary about Cunningham, his bicycle, and his camera,titled Bill Cunningham New York. The film was released on March 16, 2011.
