In 1954, Cross wrote the lyrics for the famous song I Left My Heart in San Francisco; his gay lover George Cory composed the music for the song. The song, performed by Tony Bennet in 1962, became the singer's signature tune, and in 1969 Cory and Cross's song became the official city song of San Francisco. Douglass died in Petaluma.

The loveliness of Paris seems somehow sadly gay,
The glory that was Rome is just another day,
I've been terribly alone and forgotten in Manhattan,
I'm going home to my city by the bay.

I left my heart in San Francisco, high on a hill it calls to me
To be where little cable cars climb halfway to the stars.
The morning fog may chill the air, I don't care.
My love waits there in San Francisco, above the blue and windy sea,
When I come home to you, San Francisco, your golden sun will shine for me.