Some supporters touted him as future mayor or governor. But his political star was shattered when officers under his command killed two Black Panthers in a December 1969 raid.
There's no word on the cause of death.
Hanrahan, a Democrat, was seen as a potential successor to then Mayor Richard J. Daley or a gubernatorial candidate before the Dec. 4, 1969 raid on Black Panther headquarters on Chicago's West Side in a search for illegal weapons. The raid left leader Fred Hampton and member Mark Clark, both unarmed, dead.
Hanrahan claimed police had been fired on by members of the group during the raid, pointing to bullet holes in the door. It was subsequently determined the "holes" were actually nail heads. An investigation determined that police had fired dozens of times, while only one shot was found to be fired by people inside the headquarters.
The ensuing controversy resulted in Hanrahan's defeat when he sought re-election in 1972. A special grand jury investigation resulted in the indictment of Hanrahan on conspiracy charges. He was acquitted in 1972.
Hanrahan was a graduate of the University of Notre Dame and Harvard Law School. Hanrahan practiced law after leaving the state's attorney's office. He later ran unsuccessfully for mayor, Congress and Chicago's City Council.
In addition to his wife, Geraldine, Hanrahan is survived by two sons, two daughters and several grandchildren.
The Associated Press contributed to this report.