The first All-Star Game is announced for July 6th at Comiskey Park. It will be played as part of the Chicago World’s Fair celebration and is sponsored by the Chicago Tribune. Fans will pick the players.

On May 18, 1933 — The first All-Star Game is announced for July 6th at Comiskey Park. It will be played as part of the Chicago World’s Fair celebration and is sponsored by the Chicago Tribune. Fans will pick the players.

Source:
Baseball Reference May 18