The shooting happened after 12:05 p.m. at the Canal Port Plaza area near West Illinois Avenue and Fulton Avenue in Morris, police said.
Responding officers discovered two men at the scene with gunshot wounds, police said. One man was pronounced dead at the scene and the other was taken to a local hospital to be treated for injuries.
Chopper 7 was over the scene as a large police presence could be seen.
A weapon was recovered at the scene.
The shooting is believed to be a domestic issue, police said. There is no current threat to the public.
Grundy County Dispatch has received a call from a concerned family member in Southern Illinois shortly before the shooting happened, authorities said. Both of the injured men are not from the Morris area, police said.
Illinois Avenue will remain closed between Division Street and Wauponsee Street as police continue to investigate.
No further information about the shooting was immediately available.