The music was written by Cory, with lyrics by Cross, about two amateur writers nostalgic for San Francisco after moving to New York.
Although the song was originally written for Claramae Turner, who often used it as an encore, she never got around to recording it. The song found its way to Tony Bennett through Ralph Sharon, Bennett's longtime accompanist and friends with the composers. Sharon brought the music along when he and Bennett were on tour and on their way to San Francisco's Fairmont Hotel.
A little-known fact about the song is that, prior to Tony Bennett hearing it, the song was pitched to Tennessee Ernie Ford, whom Claramae Turner suggested Cross take it to. Ford turned the song down, but in an ironic turn of events, later purchased a ranch in Lake County, California, owned by Cross's family.
In December 1961, in the famous "Venetian Room" at the Fairmont Hotel in San Francisco, Tony Bennett first sang "I Left My Heart in San Francisco". In the audience that night were San Francisco mayor George Christopher and future mayor Joseph L. Alioto. From the 1960s through the 1980s, at San Francisco's premier supper club the "Venetian Room," Bennett sang the city song.
Bennett first recorded the song at CBS Studios on 30th Street on January 23, 1962; CBS released it as the b-side of "Once Upon A Time." The A-side received no attention, and DJs began flipping the record over and playing "San Francisco." It became a hit on the pop singles chart in 1962 and spent close to a year on various other charts, achieving gold record status. It then won the top prize of Grammy Award for Record of the Year, as well as for Best Male Solo Vocal Performance. In 2001 it was ranked 23rd on an RIAA/NEA list of the most historically significant Songs of the 20th Century.
It has often been performed in public by Bennett in concert as well as on special occasions. A statue of Tony Bennett was unveiled outside the Fairmont Hotel on 19 August 2016, in honor of his 90th birthday, the hotel performance, and the song's history with San Francisco.
Bennett has said of the song,
That song helped make me a world citizen. It allowed me to live, work and sing in any city on the globe. It changed my whole life.
The Songwriters Hall of Fame gave Bennett the "Towering Performance Award" for his vocal rendition of the song.
A version by rhythm and blues singer Bobby Womack peaked at #48 on the Billboard R&B singles chart in 1969.
Also in 1969, the song was adopted by the City and County of San Francisco as one of its two official anthems, the other being the title song from the 1936 film San Francisco (1936 film).
[source : Wikipedia.org]