John Stanley Gacy was born on 20 June 1900 in Chicago, Illinois, USA. He was married to Marion Gacy. He died on 25 December 1969 in Hines, Illinois, USA.
The son of Nicholas Gacy and Veronica Jablonski, he worked as a machinist in a Chicago factory. A veteran of World War I, he was admitted to the Veterans Administration Hospital in Hines, Illinois on December 18, 1969 and died there a week later.
