The victim, 55-year-old John Ward, was riding a bicycle through Garfield Park when he was struck just before 8:30 p.m. on August 24 in the 3500 block of West Washington Boulevard.
Ward died of his injuries Thursday, Chicago police said. He was identified by the Cook County Medical Examiner's Office.
The Chicago Police Department has released a surveillance photo of the car they're searching for.
The vehicle is a blue 1997 Lincoln Town Car with the Illinois license plate ES85500.
Anyone with information has been asked to call police.
No further information about the crash was immediately available as police continue to investigate.