This was the first Chicago mayoral election since the ratification of the Twenty-sixth Amendment to the United States Constitution, which lowered the voting age from 21 to 18.

The Socialist Workers Party successfully collected signatures to petition for Willie Mae Reid to be included on the general election ballot as their nominee.

For the first time since he was elected mayor, Daley was facing what appeared to be significant opposition in a Democratic primary.

[3] Daley's health had declined by 1974, and he had taken an extended absence to recuperate after a June 1, 1974 surgery to unclog a partially blocked carotid artery.

[3] By 1975, many believed that Daley's political stature was beginning to wane, and he was seen to be out of touch with both the times and the climate of the city.

[3] Additionally, by 1975, news stories had arisen that shows political corruption and dishonesty related to Daley and his administration.

[3] Metcalfe, a one-time ally of Daley, had become critical of what he alleged was racism and brutality in the Chicago Police Department.

[5] African American State Senator Richard H. Newhouse Jr. was the first black candidate on the ballot in a Chicago mayoral election.

Despite there being a black candidate in the race, the Chicago Defender endorsed Daley, as did noted African American publisher John H.

His base of support was in white "ethnic" wards of the city, as black voters hated him due to the role of the office he oversaw as state's attorney in the raid that killed Fred Hampton.

[3] While Daley's previous reelection efforts had earned him the endorsement of the Chicago Tribune, in 1975 they abstained from endorsing in the Democratic primary declaring in its editorial that the choice presented in the primary was, "whether to stay about the rudderless galleon with rotting timbers or to take to the raging seas in a 17-foot outboard".

[3] By the end of the primary campaign, it was evident that the race had narrowed primarily to a contest between Daley and Singer.

[3] Singer brought in media consultant David Garth, who had recently been involved in Hugh Carey's successful New York gubernatorial campaign.

It was expected that, with Newhouse's historic candidacy as the first black mayoral candidate in the city's history, and with the city's most prominent black politician, Metacalfe, defecting from his onetime allegiance with Daley to endorse Singer, Daley would lose a significant share of African American support.

However, in the eleven white "ethnic" wards, Daley received 67.2% of the vote to Singer's 22.3% and Hanrahan's mere 7.2%.