The great composer/bandleader Duke Ellington died in the summer of 1974. Just a few weeks later, several dozen Chicago musicians held a festival to honor him, at the old bandshell at the south end of Grant Park. Ten thousand music lovers came, marking the first of what would become annual memorial concerts that drew crowds of up to 30,000. Then in 1978, musicians working with Chicago's Council of Fine Arts held the first John Coltrane Memorial Concert in Grant Park, another popular success. The next year the Jazz Institute of Chicago began planning its own August festival. That meant that three different groups of jazz people were working to present concerts at the end of August.
The Mayor's Office of Special Events proposed the solution: Get together to create the first Chicago Jazz Festival. It had an Ellington night, a Coltrane night, and five other programs organized by the Jazz Institute and it was held at the new Petrillo Music Shell. And 125,000 people came to listen, dance, picnic on the grass, and enjoy the birth of what was to become the most extensive free jazz festival in the world. Every year since then the Chicago Jazz Festival has been held on the week before Labor Day. The Department of Cultural Affairs and Special Events coordinates it and the Jazz Institute programs it.
Information courtesty of the City of Chicago Department of Cultural Affairs and Special Events